Residents living in the cold areas such as Harbin generally experience a residence time of approximately 6 months in chilly winter without frequent natural ventilation. To find out the influence of a short period of v...Residents living in the cold areas such as Harbin generally experience a residence time of approximately 6 months in chilly winter without frequent natural ventilation. To find out the influence of a short period of ventilation on the indoor formaldehyde concentration inside a new building, an investigation was conducted for the instance of twice ventilation in a day through window opening. The results showed that the initial concentration of formaldehyde was 3.53 -8. 48 times as high as the concentration after 10 min ventilation. After closing the window, the indoor formaldehyde concentration increased with time and followed an exponential equation of C = C0 exp（ - b ＊ t） ＋ （ a ＋ Cu, ） [ 1 - exp（ - b ＊ t） ] with correlation coefficient （ R^2 ） of 0. 945 - 0. 999, based on the statistical analysis of 14 groups of measurement data. The developed equation can be used to estimate the emission rate of indoor formaldehyde sources and the air exchange rate of the test room simultaneously.展开更多
Marx and Engles believed that man and nature develop harmoniously, when the activities of man constitute the content of nature, which is changed constantly because of the activities of man. Marx and Engles also pointe...Marx and Engles believed that man and nature develop harmoniously, when the activities of man constitute the content of nature, which is changed constantly because of the activities of man. Marx and Engles also pointed out the duality of the conquest, change and influence exerted on nature by man. On one hand, it can improve people’s living conditions and make people free from the enslavement of the nature. On the other hand, it may also lead to excessively snatching and wrecking nature, then make the deterioration of the environment and ecology out of balance. They also, from the technical angle of ecology, put forward the concrete measures to realize the harmonious symbiosis of man and nature in the development of economy. They also believed that only when socialism or communism is realized, can the conciliation of mankind and nature be realized finally. Marx and Engle’s theory of harmonious symbiosis of man and nature is of great theoretical directive significance for us to insist on the scientific development view.展开更多
In a time of the global market economy, if one wants to live harmoniously together with nature or living environment, he should not think with a theoretical mode of dualist contradiction but that of harmony and coexis...In a time of the global market economy, if one wants to live harmoniously together with nature or living environment, he should not think with a theoretical mode of dualist contradiction but that of harmony and coexistence such as ＂wholeness of man and nature＂. To illustrate this point, this paper thinks The Woman Warrior and Ballad of Eternal Sorrow are two significant texts： Ballad of Eternal Sorrow tells an ordinary, self-respecting, and life-respecting story of WANG Qi-yao and the girls like her as well as the city Shanghai. They blend into one harmonious whole： The city is like the girls and the girls match the city. Likewise, The Woman Warrior highlights the significance of naturc on the girl narrator＇s epiphany and healthy growth. The narrator comes to understand that paradoxes are the basic existent condition of human beings and so what she needs to do is to be magnanimous and balanceable in accepting these paradoxes.展开更多
By using methods of carbon footprint analysis, and impacts of population, affluence and technology （IPAT）, this article analyzes the carbon footprints of residence and travel, and their influential factors for diffe...By using methods of carbon footprint analysis, and impacts of population, affluence and technology （IPAT）, this article analyzes the carbon footprints of residence and travel, and their influential factors for different urban residential incomes, using 1,500 household questionnaires in Shijiazhuang city, Hebei province. The results show that the process of urban residents improving their living standards is also a driving factor in the increase of their carbon footprints; at the same time, the progress in technology has a positive impact on reducing the carbon footprints of urban residence. This article suggests that some measures, such as promoting energy-saving buildings and central heating supply, and establishing the convenient and comfortable public transport system, should be taken to reduce the carbon footprints of residence and travel in Shijiazhuang city.展开更多
Zoonotic transmissions of emerging pathogens from wildlife to human have shaped the history of mankind. These events have also highlighted our poor understanding of microorganisms circulated in wild animals. Coronavir...Zoonotic transmissions of emerging pathogens from wildlife to human have shaped the history of mankind. These events have also highlighted our poor understanding of microorganisms circulated in wild animals. Coronaviruses and astroviruses,which can be found from a wide range of mammals,were recently detected in bats. Strikingly,these bat viruses are genetically highly diverse and these interesting findings might help to better understand the evolution and ecology of these viruses. The discoveries of these novel bats viruses not only suggested that bats are important hosts for these virus families,but also reiterated the role of bats as a reservoir of viruses that might pose a zoonotic threat to human health.展开更多
An electricity generation planning model of the six major Chinese power grids was developed based on the General Algebraic Modeling System to evaluate and analyze the CDM （clean development mechanism）, including con...An electricity generation planning model of the six major Chinese power grids was developed based on the General Algebraic Modeling System to evaluate and analyze the CDM （clean development mechanism）, including consideration of the environmental co-benefits of reductions in air pollutants （SO~, NO~ and particulate matter） achieved by advanced electricity generation technologies incorporating CCS （carbon capture and storage）. An objective function was developed that included revenue from sales of electric power, total system cost, the cost of CO2 transport and storage, and emissions reduction co-benefits for SOx, NO~, and particulate matter. The objective function was minimized using an optimization model. We also developed a method for evaluating and analyzing the potential for transferring advanced power generation technologies into the Chinese power system through the CDM. We found that： （1） thermal power generation is predominant in the Chinese electricity system and will remain so for a long time; （2） advanced thermal plants are being installed as a result of the CDM, which contribute to decreasing emissions of CO2 and other air pollutants; and （3） CCS projects have significant potential to reduce substantial and sustained CO2 emissions from the Chinese power and industrial sectors.展开更多
The area of interest is located in the South Moravia Region at the confluence of the Jihlava, Oslava and Rokytn^i rivers. Ivan^ice spring area comprises a series of hydrologic boreholes, it is the main water source fo...The area of interest is located in the South Moravia Region at the confluence of the Jihlava, Oslava and Rokytn^i rivers. Ivan^ice spring area comprises a series of hydrologic boreholes, it is the main water source for water supply of Ivan^ice and Rosice towns and provides water for 30,000 inhabitants. The risk analysis was created on the basis of water quality monitoring, hydrogeological assessment and terrain exploration and a revision of protection zones was proposed. The spring area is situated in nitrate vulnerable zones and recently nitrate concentrations have been decreasing. Water quality evaluation results： high concentration of manganese and iron, sometimes higher concentration of ammonium and COD. This area is intensively used for agriculture and it is necessary to make a compromise solution during protection zones proposal, The regime in protection zones can not affect manganese and iron concentration （their origin is in the natural geological environment）. Therefore, water treatment plant is in operation and its modernization is proposed. Furthermore, the paper deals with spring area intensification construction of a new hydrologic borehole, and managed and unmanaged infiltration of surface water. The proposal of protection zones revision consists of reduction to a 2nd level protection zone.展开更多
Diabetes has become the epidemic of the 21 st century, and with over 90% patients with diabetes becoming at a risk of developing retinopathy, diabetic retinopathy has emerged as a major public health concern. In spite...Diabetes has become the epidemic of the 21 st century, and with over 90% patients with diabetes becoming at a risk of developing retinopathy, diabetic retinopathy has emerged as a major public health concern. In spite of cutting edge research in the field, how retina and its vasculature are damaged by the diabetic milieu remains ambiguous. The environmental factors, life style or disease process can also bring in modifications in the DNA, and these epigenetic modifications either silence or activate a gene without altering the DNA sequence. Diabetic environment up- or downregulates a number of genes in the retina, and emerging research has shown that it also facilitates epigenetic modifications. In the pathogenesis of diabetic retinopathy, the genes associated with important enzymes(e.g., mitochondrial superoxide dismutase, matrix metalloproteinase-9 and thioredoxin interacting protein) and transcriptional factors are epigenetically modified, the enzymes responsible for these epigenetic modifications are either activated or inhibited, and the levels of micro RNAs are altered. With epigenetic modifications taking an important place in diabetic retinopathy, it is now becoming critical to evaluate these modifications, and understand their impact on this slow progressing blinding disease.展开更多
Industrial symbiosis network （ISN） is an efficient organizational form for improving resource recycling and efficiency in industrial cluster district. Because of the variety of industrial cluster district formation ...Industrial symbiosis network （ISN） is an efficient organizational form for improving resource recycling and efficiency in industrial cluster district. Because of the variety of industrial cluster district formation model, the industrial symbiosis network is different with each other. Based on the circular economy theory, combing with international tendency of cluster district, the paper puts forward the relying-on-oriented industrial symbiosis network. Meanwhile, it also analyzes its organizational mechanism, operating pattern and environmental performance. Through the above efforts, we hope it could be helpful for industry cluster district sustainable development in China.展开更多
The complex interplay between symbiotic bacteria and host immunity plays a key role in shaping intestinal homeostasis and maintaining host health. Paneth cells, as one of the major producers of antimicrobial peptides ...The complex interplay between symbiotic bacteria and host immunity plays a key role in shaping intestinal homeostasis and maintaining host health. Paneth cells, as one of the major producers of antimicrobial peptides in the intestine under steady-state conditions, play a vital role in regulating intestinal flora. Many studies on inflammatory bowel disease(IBD)-associated genes have put Paneth cells at the center of IBD pathogenesis. In this perspective, we focus on mechanistic studies of different cellular processes in Paneth cells that are regulated by various IBD-associated susceptibility genes, and we discuss the hypothesis that Paneth cells function as the central hub for sensing and regulating intestinal flora in the maintenance of intestinal homeostasis.展开更多
To introduce a safe and specific appr oach of 13 C magnetic resonance spectrum ( 13 C MRS) spectroscopy and investigate the alterations in hepatic anabolism. Methods: Relative anaplerotic, pyruvate recycling and gluco...To introduce a safe and specific appr oach of 13 C magnetic resonance spectrum ( 13 C MRS) spectroscopy and investigate the alterations in hepatic anabolism. Methods: Relative anaplerotic, pyruvate recycling and gluconeog enic fluxes were measured by 13 C MRS isotopomer ana lysis of blood glucose from rats with 40% body surface area burn injury, and fro m rat s exposed to sham injury. A short chain fatty acid, [U 13 C] propionate which was avidly extracted by the liver, was infused intravenously to deliver 13 C into the citric acid cycle. Proton decoupled 13 C MRS of deproteinized plasma or extracts of the freeze clamped liver were used to determine the distribution of 13 C in blood or hepatic glucose.Results: There was no difference in the multiplets detected in the glucose carbon 2 anomer from blood or liver after 45 or 60 minutes of the i nfusion of the propionate, indicating that steady state isotopic conditions wer e achiev ed. Gluconeogenesis relative to citric acid cycle flux was not altered by burn i njury; in both sham and burn groups the rate of glucose production was about equ al to flux through citrate synthase. In the sham group of animals, the rate of e ntry of carbon skeletons into the citric acid cycle was about 4 times than that in the burn group. Similarly, flux through pyruvate kinase (again relative to ci trate synthase) was significantly increased after the burn injury. Conclusions: Since results from analysis of the blood glucose a re the same as that of the hepatic glucose, 13 C dis tribution in the glucose and hepatic metabolism can be assessed based on the 13 C MRS analysis of the blood glucose.展开更多
Urban public health is an important global issue, and receives extensive attention. It is necessary to compare urban public health status among different cities, so that each city can define its own health patterns an...Urban public health is an important global issue, and receives extensive attention. It is necessary to compare urban public health status among different cities, so that each city can define its own health patterns and limiting factors. The following assessment indicators were established to evaluate urban public health status： living conditions, physical health, education and culture, envir- onmental quality, and social security. A weighted-sum model was used in combination with these indicators to compare the urban public health status in four cities-- Beijing, New York, London, and Tokyo--using data for 2000-2009. Although the urban public health level of Beijing was lower than that of the other cities, it showed the greatest increase in this level over the study period. Different patterns of urban public health were identified： London had the most balanced, steady pattern （almost all factors performed well and developed stably）; New York and Tokyo showed balanced, but unsteady patterns （most factors remained high, though social security and environ- mental quality fluctuated）; Beijing had the most unba- lanced, unsteady pattern （the different factors were at different levels, and education and culture and social security fluctuated）. For enhanced urban public health status, environmental quality and education and culture clearly need to be improved in Beijing. This study demonstrates that a comparison of different cities is helpful in identifying limiting factors for urban public health and providing an orientation for future urban development.展开更多
Dragonfly hindwing inspired two different flapping wing morphologies are investigated for flexible flapping wing micro air vehicles(FWMAV)applications.The wing skin is developed using 1%functionalized carbon nanotubes...Dragonfly hindwing inspired two different flapping wing morphologies are investigated for flexible flapping wing micro air vehicles(FWMAV)applications.The wing skin is developed using 1%functionalized carbon nanotubes reinforced polypropylene nanocomposites with carbon fiber epoxy composite strands as venation pattern.The resonance frequencies are the fundamental information for biomimicking and were calculated theoretically from stiffness data.Bending dominated first natural frequency was obtained from flexural stiffness data and found close to the flapping frequency of natural dragonfly hindwing.Twisting dominated second natural frequency was obtained from torsional stiffness,which revealed that the artificial wings can be fabricated thinner.The flapping frequency of artificial wings is unaffected by the twisting deformation.The bending and twisting dominated mode shapes are also studied using the digital image correlation(DIC)system.To verify the static and dynamic results,finite element simulations are performed that agree with experimental findings.It was found that the proposed flexible nanocomposite wing skin can control the bending and twisting dominated frequencies by tailoring the wing morphology without affecting the mode shapes of deformation.展开更多
基金Sponsored by the Scientific and Technically Key Project of Heilongjiang Province(Grant No.GC04C213).
文摘Residents living in the cold areas such as Harbin generally experience a residence time of approximately 6 months in chilly winter without frequent natural ventilation. To find out the influence of a short period of ventilation on the indoor formaldehyde concentration inside a new building, an investigation was conducted for the instance of twice ventilation in a day through window opening. The results showed that the initial concentration of formaldehyde was 3.53 -8. 48 times as high as the concentration after 10 min ventilation. After closing the window, the indoor formaldehyde concentration increased with time and followed an exponential equation of C = C0 exp（ - b ＊ t） ＋ （ a ＋ Cu, ） [ 1 - exp（ - b ＊ t） ] with correlation coefficient （ R^2 ） of 0. 945 - 0. 999, based on the statistical analysis of 14 groups of measurement data. The developed equation can be used to estimate the emission rate of indoor formaldehyde sources and the air exchange rate of the test room simultaneously.
文摘Marx and Engles believed that man and nature develop harmoniously, when the activities of man constitute the content of nature, which is changed constantly because of the activities of man. Marx and Engles also pointed out the duality of the conquest, change and influence exerted on nature by man. On one hand, it can improve people’s living conditions and make people free from the enslavement of the nature. On the other hand, it may also lead to excessively snatching and wrecking nature, then make the deterioration of the environment and ecology out of balance. They also, from the technical angle of ecology, put forward the concrete measures to realize the harmonious symbiosis of man and nature in the development of economy. They also believed that only when socialism or communism is realized, can the conciliation of mankind and nature be realized finally. Marx and Engle’s theory of harmonious symbiosis of man and nature is of great theoretical directive significance for us to insist on the scientific development view.
文摘In a time of the global market economy, if one wants to live harmoniously together with nature or living environment, he should not think with a theoretical mode of dualist contradiction but that of harmony and coexistence such as ＂wholeness of man and nature＂. To illustrate this point, this paper thinks The Woman Warrior and Ballad of Eternal Sorrow are two significant texts： Ballad of Eternal Sorrow tells an ordinary, self-respecting, and life-respecting story of WANG Qi-yao and the girls like her as well as the city Shanghai. They blend into one harmonious whole： The city is like the girls and the girls match the city. Likewise, The Woman Warrior highlights the significance of naturc on the girl narrator＇s epiphany and healthy growth. The narrator comes to understand that paradoxes are the basic existent condition of human beings and so what she needs to do is to be magnanimous and balanceable in accepting these paradoxes.
基金supported under the French Institute of Veolia Environment(IVE) program
文摘By using methods of carbon footprint analysis, and impacts of population, affluence and technology （IPAT）, this article analyzes the carbon footprints of residence and travel, and their influential factors for different urban residential incomes, using 1,500 household questionnaires in Shijiazhuang city, Hebei province. The results show that the process of urban residents improving their living standards is also a driving factor in the increase of their carbon footprints; at the same time, the progress in technology has a positive impact on reducing the carbon footprints of urban residence. This article suggests that some measures, such as promoting energy-saving buildings and central heating supply, and establishing the convenient and comfortable public transport system, should be taken to reduce the carbon footprints of residence and travel in Shijiazhuang city.
基金supported by the National Institute of Allergy and Infectious Diseases (NIAID contract HHSN266200700005C)European Research Project SARS-DTV (contract no: SP22-CT-2004)
文摘Zoonotic transmissions of emerging pathogens from wildlife to human have shaped the history of mankind. These events have also highlighted our poor understanding of microorganisms circulated in wild animals. Coronaviruses and astroviruses,which can be found from a wide range of mammals,were recently detected in bats. Strikingly,these bat viruses are genetically highly diverse and these interesting findings might help to better understand the evolution and ecology of these viruses. The discoveries of these novel bats viruses not only suggested that bats are important hosts for these virus families,but also reiterated the role of bats as a reservoir of viruses that might pose a zoonotic threat to human health.
文摘An electricity generation planning model of the six major Chinese power grids was developed based on the General Algebraic Modeling System to evaluate and analyze the CDM （clean development mechanism）, including consideration of the environmental co-benefits of reductions in air pollutants （SO~, NO~ and particulate matter） achieved by advanced electricity generation technologies incorporating CCS （carbon capture and storage）. An objective function was developed that included revenue from sales of electric power, total system cost, the cost of CO2 transport and storage, and emissions reduction co-benefits for SOx, NO~, and particulate matter. The objective function was minimized using an optimization model. We also developed a method for evaluating and analyzing the potential for transferring advanced power generation technologies into the Chinese power system through the CDM. We found that： （1） thermal power generation is predominant in the Chinese electricity system and will remain so for a long time; （2） advanced thermal plants are being installed as a result of the CDM, which contribute to decreasing emissions of CO2 and other air pollutants; and （3） CCS projects have significant potential to reduce substantial and sustained CO2 emissions from the Chinese power and industrial sectors.
文摘The area of interest is located in the South Moravia Region at the confluence of the Jihlava, Oslava and Rokytn^i rivers. Ivan^ice spring area comprises a series of hydrologic boreholes, it is the main water source for water supply of Ivan^ice and Rosice towns and provides water for 30,000 inhabitants. The risk analysis was created on the basis of water quality monitoring, hydrogeological assessment and terrain exploration and a revision of protection zones was proposed. The spring area is situated in nitrate vulnerable zones and recently nitrate concentrations have been decreasing. Water quality evaluation results： high concentration of manganese and iron, sometimes higher concentration of ammonium and COD. This area is intensively used for agriculture and it is necessary to make a compromise solution during protection zones proposal, The regime in protection zones can not affect manganese and iron concentration （their origin is in the natural geological environment）. Therefore, water treatment plant is in operation and its modernization is proposed. Furthermore, the paper deals with spring area intensification construction of a new hydrologic borehole, and managed and unmanaged infiltration of surface water. The proposal of protection zones revision consists of reduction to a 2nd level protection zone.
文摘Diabetes has become the epidemic of the 21 st century, and with over 90% patients with diabetes becoming at a risk of developing retinopathy, diabetic retinopathy has emerged as a major public health concern. In spite of cutting edge research in the field, how retina and its vasculature are damaged by the diabetic milieu remains ambiguous. The environmental factors, life style or disease process can also bring in modifications in the DNA, and these epigenetic modifications either silence or activate a gene without altering the DNA sequence. Diabetic environment up- or downregulates a number of genes in the retina, and emerging research has shown that it also facilitates epigenetic modifications. In the pathogenesis of diabetic retinopathy, the genes associated with important enzymes(e.g., mitochondrial superoxide dismutase, matrix metalloproteinase-9 and thioredoxin interacting protein) and transcriptional factors are epigenetically modified, the enzymes responsible for these epigenetic modifications are either activated or inhibited, and the levels of micro RNAs are altered. With epigenetic modifications taking an important place in diabetic retinopathy, it is now becoming critical to evaluate these modifications, and understand their impact on this slow progressing blinding disease.
基金This research is partly supported the National Natural Science Foundation of China（70773008, 70602021, 70403008）, the Humanities and Social Sciences Foundation of MOE of Ghina （05JG630065）, the National Soft Science Research Planning of the MOST （2006GXS2B024）, the Natural Science Foundation of Beijing （9073019）, the Philosophical and Social Science Foundation of Beijing （06BaJG038）, the Excellent Young Scholars Research Fund of BIT （2006Y0817） and the Fundamental Research Fund of BIT （20060842003）.
文摘Industrial symbiosis network （ISN） is an efficient organizational form for improving resource recycling and efficiency in industrial cluster district. Because of the variety of industrial cluster district formation model, the industrial symbiosis network is different with each other. Based on the circular economy theory, combing with international tendency of cluster district, the paper puts forward the relying-on-oriented industrial symbiosis network. Meanwhile, it also analyzes its organizational mechanism, operating pattern and environmental performance. Through the above efforts, we hope it could be helpful for industry cluster district sustainable development in China.
文摘The complex interplay between symbiotic bacteria and host immunity plays a key role in shaping intestinal homeostasis and maintaining host health. Paneth cells, as one of the major producers of antimicrobial peptides in the intestine under steady-state conditions, play a vital role in regulating intestinal flora. Many studies on inflammatory bowel disease(IBD)-associated genes have put Paneth cells at the center of IBD pathogenesis. In this perspective, we focus on mechanistic studies of different cellular processes in Paneth cells that are regulated by various IBD-associated susceptibility genes, and we discuss the hypothesis that Paneth cells function as the central hub for sensing and regulating intestinal flora in the maintenance of intestinal homeostasis.
文摘To introduce a safe and specific appr oach of 13 C magnetic resonance spectrum ( 13 C MRS) spectroscopy and investigate the alterations in hepatic anabolism. Methods: Relative anaplerotic, pyruvate recycling and gluconeog enic fluxes were measured by 13 C MRS isotopomer ana lysis of blood glucose from rats with 40% body surface area burn injury, and fro m rat s exposed to sham injury. A short chain fatty acid, [U 13 C] propionate which was avidly extracted by the liver, was infused intravenously to deliver 13 C into the citric acid cycle. Proton decoupled 13 C MRS of deproteinized plasma or extracts of the freeze clamped liver were used to determine the distribution of 13 C in blood or hepatic glucose.Results: There was no difference in the multiplets detected in the glucose carbon 2 anomer from blood or liver after 45 or 60 minutes of the i nfusion of the propionate, indicating that steady state isotopic conditions wer e achiev ed. Gluconeogenesis relative to citric acid cycle flux was not altered by burn i njury; in both sham and burn groups the rate of glucose production was about equ al to flux through citrate synthase. In the sham group of animals, the rate of e ntry of carbon skeletons into the citric acid cycle was about 4 times than that in the burn group. Similarly, flux through pyruvate kinase (again relative to ci trate synthase) was significantly increased after the burn injury. Conclusions: Since results from analysis of the blood glucose a re the same as that of the hepatic glucose, 13 C dis tribution in the glucose and hepatic metabolism can be assessed based on the 13 C MRS analysis of the blood glucose.
基金Financial support is provided by the National Natural Science Foundation of China （Grant No. 40901269）, the Program for New Century Excellent Talents in University （NCET-09-0226）, the National Science Foundation for Innovative Research Group （No. 51121003）, and the Fundamental Research Funds for the Central Universities. The authors would also thank the help of the editor and the comments of the reviewers, which significantly improved the quality of this paper.
文摘Urban public health is an important global issue, and receives extensive attention. It is necessary to compare urban public health status among different cities, so that each city can define its own health patterns and limiting factors. The following assessment indicators were established to evaluate urban public health status： living conditions, physical health, education and culture, envir- onmental quality, and social security. A weighted-sum model was used in combination with these indicators to compare the urban public health status in four cities-- Beijing, New York, London, and Tokyo--using data for 2000-2009. Although the urban public health level of Beijing was lower than that of the other cities, it showed the greatest increase in this level over the study period. Different patterns of urban public health were identified： London had the most balanced, steady pattern （almost all factors performed well and developed stably）; New York and Tokyo showed balanced, but unsteady patterns （most factors remained high, though social security and environ- mental quality fluctuated）; Beijing had the most unba- lanced, unsteady pattern （the different factors were at different levels, and education and culture and social security fluctuated）. For enhanced urban public health status, environmental quality and education and culture clearly need to be improved in Beijing. This study demonstrates that a comparison of different cities is helpful in identifying limiting factors for urban public health and providing an orientation for future urban development.
文摘Dragonfly hindwing inspired two different flapping wing morphologies are investigated for flexible flapping wing micro air vehicles(FWMAV)applications.The wing skin is developed using 1%functionalized carbon nanotubes reinforced polypropylene nanocomposites with carbon fiber epoxy composite strands as venation pattern.The resonance frequencies are the fundamental information for biomimicking and were calculated theoretically from stiffness data.Bending dominated first natural frequency was obtained from flexural stiffness data and found close to the flapping frequency of natural dragonfly hindwing.Twisting dominated second natural frequency was obtained from torsional stiffness,which revealed that the artificial wings can be fabricated thinner.The flapping frequency of artificial wings is unaffected by the twisting deformation.The bending and twisting dominated mode shapes are also studied using the digital image correlation(DIC)system.To verify the static and dynamic results,finite element simulations are performed that agree with experimental findings.It was found that the proposed flexible nanocomposite wing skin can control the bending and twisting dominated frequencies by tailoring the wing morphology without affecting the mode shapes of deformation.
