A simple method presenting linear single strain DNA （LssDNA） sequence with natural numbers is introduced in this paper. The method presents LssDNA correspondingly with the numerals 1, 2, 3 and 4. After calculation, ...A simple method presenting linear single strain DNA （LssDNA） sequence with natural numbers is introduced in this paper. The method presents LssDNA correspondingly with the numerals 1, 2, 3 and 4. After calculation, the sequence can be coded in natural numbers which can also be decoded into the DNA sequence. Thus, an LssDNA sequence can be expressed in a natural number and a dot at coordinate axes. In the future, a new LssDNA sequences database termed ＂DotBank＂ would be realized in which each LssDNA sequence is determined as a dot.展开更多
Alpine-cold regions are characterized as hypoxia,strong wind,heavy rain,cold climate,huge temperature difference between day and night,and vertical climate. All these make it difficult for an emergency rescue when a n...Alpine-cold regions are characterized as hypoxia,strong wind,heavy rain,cold climate,huge temperature difference between day and night,and vertical climate. All these make it difficult for an emergency rescue when a natural disaster such as earthquake happens. Based on the characteristics of emergency rescue in alpinecold region,several multifunctional protective equipments have been developed by the Quartermaster Equipment Institute of General Logistics Departmen(tGLD)of the Chinese People's Liberation Army(CPLA). These equipments are lightweight,durable and environment adaptable.展开更多
In view of the fact that climate-related disasters are already taking a heavy toll, causing massive damage to crops and infrastructure and forcing some people to flee their homes, however, the potential impacts of cli...In view of the fact that climate-related disasters are already taking a heavy toll, causing massive damage to crops and infrastructure and forcing some people to flee their homes, however, the potential impacts of climate change are likely to trigger adaptive responses that influence environmental and socio-economic drivers of food system performance in positive as well as negative ways. This paper was conducted through the collection of some research materials with the projected balance of these various climate impacts on food system performance and food security outcomes at the local and global levels. More so that, food security is likely to be affected by climate change in several ways： food security depends not only on the direct impact of climate change on food production but also on its indirect impact on human nutrition and health, economic growth, trade flows and food aid policy. The paper further examined the effectiveness of managing new risks and uncertainty, improving the quality of information and its use, monitoring weather and improving scientific understanding of climate change, promoting insurance schemes, maintaining biodiversity and access to fund as some of the crucial measures for adaptation. The large amount of resources that would be necessary to avoid the worst case scenario suggests the necessity of continued support from the international community to improve food security at the local and global levels as a whole.展开更多
Cubic equations of state(EOSs) are simple and easy at calculation. One way of improving the accuracy of a cubic EOS is through the modification of temperature-dependent energy parameter by using alpha-function.The ind...Cubic equations of state(EOSs) are simple and easy at calculation. One way of improving the accuracy of a cubic EOS is through the modification of temperature-dependent energy parameter by using alpha-function.The industrial applications of natural gas are very wide and as a result, prediction of thermodynamic properties and phase behavior of natural gas is an important part of design for such processes. In this work we develop a newα-function for the Peng-Robinson(PR) EOS with the parameters optimized especially for natural gas components.The parameters are generalized as a linear function of acentric factor. The results are compared to the predictions from original PR EOS and other α-functions in literature. It is shown that the new α-function presents a good accuracy with the average deviation of 1.42% for natural gas components.展开更多
Invariably, it is the poorest of the poor who are mostly affected by perverse disasters, policies and laws. A major concern in disaster research is to explore the relationship between shock experiences and victims＇ p...Invariably, it is the poorest of the poor who are mostly affected by perverse disasters, policies and laws. A major concern in disaster research is to explore the relationship between shock experiences and victims＇ perceptions of risk, as well as their possible effect on victims＇ behavior for resilience and adaptation. We explore this relationship on victimized households of the 1986 Lake Nyos disaster, employing a quasi-experimental design. Matching was done with non-affected households. Both groups affected and non-affected households were of adequate size, and subject to the same questionnaire. Selection of （470） test and matching households was purposely limited to nine of the ten towns accommodating both survivors and non survivors of the examined disaster. A list constructed with traditional rulers in each village allowed for random sampling of non victims for comparative analysis. We then compare households affected by the disaster with those who were not. The results reveal differentiated perceptions of risk and management behavior contingent on whether households experienced the shock or not. However, solidarity and reciprocity remained extremely high and not significantly different amongst both household types, suggesting resilience of endogenous, informal risk response mechanisms to natural shocks. The article concludes that analyzing risk perceptions can help explain why some individuals, households or communities may be resilient to shocks and others not. We argue for a combination of subjective perceptions and objective shock analysis, especially if the analyst hopes to influence policy.展开更多
The feasibility of rhenium （Re） production by irradiating tungsten （W） metal in a medium size fast reactor was evaluated by using a Monte Carlo code. The fast reactor can produce about 50 kilograms of Re per every...The feasibility of rhenium （Re） production by irradiating tungsten （W） metal in a medium size fast reactor was evaluated by using a Monte Carlo code. The fast reactor can produce about 50 kilograms of Re per every 3 years, which corresponds 10% of Japanese domestic production. The specific activity of Re can be reduced below the exemption level or even the natural Re level if W and osmium is separated after the irradiation. The use of ZrD1.7 moderator reduces the specific activity by half compared to that of ZrH1.7 case, and even the no moderator case is permissible to produce the production of Re which has lower specific reactivity than that of natural Re.展开更多
Generally the irreducible water saturation of low permeability gas reservoir is quite high which leads to the permeability stress sensibility and threshold pressure gradient. Under the assumption that permeability var...Generally the irreducible water saturation of low permeability gas reservoir is quite high which leads to the permeability stress sensibility and threshold pressure gradient. Under the assumption that permeability varies with experimental law of the pseudo pressure drop, according to concepts of perturbable ellipses and equivalent developing regulations, the calculation method of stable production of hydraulically fractured gas well in low permeability reservoirs is investigated with threshold pressure. And productivity curve is drawn and analyzed. The result shows that, permeability modulus and threshold pressure have effect on production of fractured gas well. The higher the permeability modulus and the threshold pressure, the lower the production is. Therefore, the impact of stress sensitive and threshold pressure must he considered when analyzing the productivity of vertical fracture well in low permeability gas reservoir.展开更多
Crushed fine aggregates are widely used for full or partial replacement of natural sands in concretes. The crushed sands present different characteristics from the natural sand, especially if taking into account the c...Crushed fine aggregates are widely used for full or partial replacement of natural sands in concretes. The crushed sands present different characteristics from the natural sand, especially if taking into account the content of microfine particle, the distribution of particle sizes, the shape features, besides the different lithological origin. From the rheological point of view, the crushed sands frequently provide mixtures with high yield stress, high viscosity, high cohesion and internal friction, which hinders its use in concrete. This study is focused on the evaluation of the rheological behavior of concrete mortar phase when using different lithological types of crushed sand in total replacement of natural sand. The lithological types surveyed were granite, calcitic limestone, dolomite limestone and mica schist. Each of these sand types was studied in two ways： in natura and with adjusted grading curve. The results show the best performance of calcitic limestone providing lower viscosities and lower yield stress in mortars.展开更多
Since 1978, Brazil has invested into bio-fuels alternatives, especially ethanol from sugar-cane processing and that has increased the bagasse production, which requires proper destination and a potential use of such b...Since 1978, Brazil has invested into bio-fuels alternatives, especially ethanol from sugar-cane processing and that has increased the bagasse production, which requires proper destination and a potential use of such biomass is the gasification process. In the present study, a conceptual design of a gasification system to convert sugar cane bagasse into syngas is presented, which considers air as gasification agent in a flexible configuration of bubbling fluidized bed reactor operating from atmospheric pressure up to 2 MPa, providing a net power output （referred at gas cold conditions） of 3 MWt and 66 MWt, respectively. In this last case, the gas may be used not just as a fuel for gas turbines and internal combustion engines for power generation but also to feed Fischer-Tropsch processes. The optimized conceptual design of the gasifier is described here and was achieved using the CSFMB （Comprehensive Simulator of Fluidized and Moving Bed Equipment）. Simulations predicted the production of gas with high heating value as well stable operations at both conditions. The conceptual design would be followed by the detailed one and construction. Tests would be carried in the near future and would allow direct comparison between the calculated and experimental results.展开更多
Mimicry is widely used to exemplify natural selection＇s power in promoting adaptation. Nonetheless, it has become increasingly clear that mimicry is frequently imprecise. Indeed, the phenotypic match is often poor be...Mimicry is widely used to exemplify natural selection＇s power in promoting adaptation. Nonetheless, it has become increasingly clear that mimicry is frequently imprecise. Indeed, the phenotypic match is often poor between mimics and models in many Batesian mimicry complexes and among co-mimics in many Mtillerian mimicry complexes. Here, we consider whether such imperfect mimicry represents an evolutionary compromise between predator-mediated selection favoring mimetic conver- gence on the one hand and competitively mediated selection favoring divergence on the other hand. Specifically, for mimicry to be effective, mimics and their models/co-mimics should occur together. Yet, co-occurring species that are phenotypically similar often compete for resources, successful reproduction, or both. As an adaptive response to minimize such costly interactions, in-teracting species may diverge phenotypically through an evolutionary process known as character displacement. Such divergence between mimics and their models/co-mimics may thereby result in imperfect mimicry. We review the various ways in which character displacement could promote imprecise mimicry, describe the conditions under which this process may be especially likely to produce imperfect mimicry, examine a possible case study, and discuss avenues for future research. Generally, character displacement may play an underappreciated role in fostering inexact mimicry .展开更多
基金Supported by the National High Technology Research and Development Program of China (863 Program) (No.2003AA622030)
文摘A simple method presenting linear single strain DNA （LssDNA） sequence with natural numbers is introduced in this paper. The method presents LssDNA correspondingly with the numerals 1, 2, 3 and 4. After calculation, the sequence can be coded in natural numbers which can also be decoded into the DNA sequence. Thus, an LssDNA sequence can be expressed in a natural number and a dot at coordinate axes. In the future, a new LssDNA sequences database termed ＂DotBank＂ would be realized in which each LssDNA sequence is determined as a dot.
文摘Alpine-cold regions are characterized as hypoxia,strong wind,heavy rain,cold climate,huge temperature difference between day and night,and vertical climate. All these make it difficult for an emergency rescue when a natural disaster such as earthquake happens. Based on the characteristics of emergency rescue in alpinecold region,several multifunctional protective equipments have been developed by the Quartermaster Equipment Institute of General Logistics Departmen(tGLD)of the Chinese People's Liberation Army(CPLA). These equipments are lightweight,durable and environment adaptable.
文摘In view of the fact that climate-related disasters are already taking a heavy toll, causing massive damage to crops and infrastructure and forcing some people to flee their homes, however, the potential impacts of climate change are likely to trigger adaptive responses that influence environmental and socio-economic drivers of food system performance in positive as well as negative ways. This paper was conducted through the collection of some research materials with the projected balance of these various climate impacts on food system performance and food security outcomes at the local and global levels. More so that, food security is likely to be affected by climate change in several ways： food security depends not only on the direct impact of climate change on food production but also on its indirect impact on human nutrition and health, economic growth, trade flows and food aid policy. The paper further examined the effectiveness of managing new risks and uncertainty, improving the quality of information and its use, monitoring weather and improving scientific understanding of climate change, promoting insurance schemes, maintaining biodiversity and access to fund as some of the crucial measures for adaptation. The large amount of resources that would be necessary to avoid the worst case scenario suggests the necessity of continued support from the international community to improve food security at the local and global levels as a whole.
文摘Cubic equations of state(EOSs) are simple and easy at calculation. One way of improving the accuracy of a cubic EOS is through the modification of temperature-dependent energy parameter by using alpha-function.The industrial applications of natural gas are very wide and as a result, prediction of thermodynamic properties and phase behavior of natural gas is an important part of design for such processes. In this work we develop a newα-function for the Peng-Robinson(PR) EOS with the parameters optimized especially for natural gas components.The parameters are generalized as a linear function of acentric factor. The results are compared to the predictions from original PR EOS and other α-functions in literature. It is shown that the new α-function presents a good accuracy with the average deviation of 1.42% for natural gas components.
文摘Invariably, it is the poorest of the poor who are mostly affected by perverse disasters, policies and laws. A major concern in disaster research is to explore the relationship between shock experiences and victims＇ perceptions of risk, as well as their possible effect on victims＇ behavior for resilience and adaptation. We explore this relationship on victimized households of the 1986 Lake Nyos disaster, employing a quasi-experimental design. Matching was done with non-affected households. Both groups affected and non-affected households were of adequate size, and subject to the same questionnaire. Selection of （470） test and matching households was purposely limited to nine of the ten towns accommodating both survivors and non survivors of the examined disaster. A list constructed with traditional rulers in each village allowed for random sampling of non victims for comparative analysis. We then compare households affected by the disaster with those who were not. The results reveal differentiated perceptions of risk and management behavior contingent on whether households experienced the shock or not. However, solidarity and reciprocity remained extremely high and not significantly different amongst both household types, suggesting resilience of endogenous, informal risk response mechanisms to natural shocks. The article concludes that analyzing risk perceptions can help explain why some individuals, households or communities may be resilient to shocks and others not. We argue for a combination of subjective perceptions and objective shock analysis, especially if the analyst hopes to influence policy.
文摘The feasibility of rhenium （Re） production by irradiating tungsten （W） metal in a medium size fast reactor was evaluated by using a Monte Carlo code. The fast reactor can produce about 50 kilograms of Re per every 3 years, which corresponds 10% of Japanese domestic production. The specific activity of Re can be reduced below the exemption level or even the natural Re level if W and osmium is separated after the irradiation. The use of ZrD1.7 moderator reduces the specific activity by half compared to that of ZrH1.7 case, and even the no moderator case is permissible to produce the production of Re which has lower specific reactivity than that of natural Re.
文摘Generally the irreducible water saturation of low permeability gas reservoir is quite high which leads to the permeability stress sensibility and threshold pressure gradient. Under the assumption that permeability varies with experimental law of the pseudo pressure drop, according to concepts of perturbable ellipses and equivalent developing regulations, the calculation method of stable production of hydraulically fractured gas well in low permeability reservoirs is investigated with threshold pressure. And productivity curve is drawn and analyzed. The result shows that, permeability modulus and threshold pressure have effect on production of fractured gas well. The higher the permeability modulus and the threshold pressure, the lower the production is. Therefore, the impact of stress sensitive and threshold pressure must he considered when analyzing the productivity of vertical fracture well in low permeability gas reservoir.
文摘Crushed fine aggregates are widely used for full or partial replacement of natural sands in concretes. The crushed sands present different characteristics from the natural sand, especially if taking into account the content of microfine particle, the distribution of particle sizes, the shape features, besides the different lithological origin. From the rheological point of view, the crushed sands frequently provide mixtures with high yield stress, high viscosity, high cohesion and internal friction, which hinders its use in concrete. This study is focused on the evaluation of the rheological behavior of concrete mortar phase when using different lithological types of crushed sand in total replacement of natural sand. The lithological types surveyed were granite, calcitic limestone, dolomite limestone and mica schist. Each of these sand types was studied in two ways： in natura and with adjusted grading curve. The results show the best performance of calcitic limestone providing lower viscosities and lower yield stress in mortars.
文摘Since 1978, Brazil has invested into bio-fuels alternatives, especially ethanol from sugar-cane processing and that has increased the bagasse production, which requires proper destination and a potential use of such biomass is the gasification process. In the present study, a conceptual design of a gasification system to convert sugar cane bagasse into syngas is presented, which considers air as gasification agent in a flexible configuration of bubbling fluidized bed reactor operating from atmospheric pressure up to 2 MPa, providing a net power output （referred at gas cold conditions） of 3 MWt and 66 MWt, respectively. In this last case, the gas may be used not just as a fuel for gas turbines and internal combustion engines for power generation but also to feed Fischer-Tropsch processes. The optimized conceptual design of the gasifier is described here and was achieved using the CSFMB （Comprehensive Simulator of Fluidized and Moving Bed Equipment）. Simulations predicted the production of gas with high heating value as well stable operations at both conditions. The conceptual design would be followed by the detailed one and construction. Tests would be carried in the near future and would allow direct comparison between the calculated and experimental results.
基金We thank Karin Pfennig, the members of the Pfennig lab, and two anonymous referees for helpful comments. We also thank Zhi-Yun Jia for inviting us to submit this paper and the U.S. National Science Foundation for fund-ing our research on mimicry and character displacement.
文摘Mimicry is widely used to exemplify natural selection＇s power in promoting adaptation. Nonetheless, it has become increasingly clear that mimicry is frequently imprecise. Indeed, the phenotypic match is often poor between mimics and models in many Batesian mimicry complexes and among co-mimics in many Mtillerian mimicry complexes. Here, we consider whether such imperfect mimicry represents an evolutionary compromise between predator-mediated selection favoring mimetic conver- gence on the one hand and competitively mediated selection favoring divergence on the other hand. Specifically, for mimicry to be effective, mimics and their models/co-mimics should occur together. Yet, co-occurring species that are phenotypically similar often compete for resources, successful reproduction, or both. As an adaptive response to minimize such costly interactions, in-teracting species may diverge phenotypically through an evolutionary process known as character displacement. Such divergence between mimics and their models/co-mimics may thereby result in imperfect mimicry. We review the various ways in which character displacement could promote imprecise mimicry, describe the conditions under which this process may be especially likely to produce imperfect mimicry, examine a possible case study, and discuss avenues for future research. Generally, character displacement may play an underappreciated role in fostering inexact mimicry .
