This paper suggests explanations for otherwise seemingly unexplained data about elementary particles and cosmology. The explanations have bases in coordinate-based modeling and in integer-based characterizations for s...This paper suggests explanations for otherwise seemingly unexplained data about elementary particles and cosmology. The explanations have bases in coordinate-based modeling and in integer-based characterizations for some catalogs. One catalog features properties—including charge, mass, and angular momentum—of objects. Another catalog features all known and some possible elementary particles. Assumptions include that multipole-expansion mathematics has uses regarding long-range interactions, such as gravity, and that nature includes six isomers of all elementary particles other than long-range-interaction bosons. One isomer associates with ordinary matter. Five isomers are associated with dark matter. Multipole notions help explain large-scale aspects such as the rate of expansion of the universe.展开更多
Biological invasion poses a huge threat to ecological security.Spartina alterniflora was introduced into China in 1979,and its arrival corresponded with negative effects on native ecosystems.To explore geographical va...Biological invasion poses a huge threat to ecological security.Spartina alterniflora was introduced into China in 1979,and its arrival corresponded with negative effects on native ecosystems.To explore geographical variation of its expansion rate in coastal China,we selected 43 S.alterniflora sites from Tianjin Coastal New Area to Beihai.The area expansion rate,expansion rate paralleling and vertical to the shoreline were analysed based on Landsat images and field survey in 2015.Simple Ocean Data Assimilation(SODA)and climate data were collected to statistically analyse the influential factors of expansion rate.Results showed that significant difference of S.alterniflora area expansion rate among different latitude zones(P<0.01),increasing from 6.08%at southern(21°N–23°N)to 19.87% in Bohai Bay(37°N–39°N)along latitude gradient.There was a significant difference in expansion rate vertical to shoreline in different latitude zones(P<0.01)with the largest occurring in Bohai Bay(256m/yr,37°N–39°N),and showed an decreasing tendency gradually from north to south.No significant difference and latitudinal clines in expansion rate paralleling to shoreline were observed.Expansion rate had significant negative correlation with mean seawater temperature,the lowest seawater temperature,current zonal velocity and meridional velocity and presented a reducing trend as these biotic factors increased;however,they were not significantly correlated with the highest seawater temperature and mean seawater salinity.We identified significant correlations between expansion rate and annual mean temperature,the lowest temperature in January and annual precipitation,but there was little correlation with annual diurnal difference in temperature and the highest temperature in July.The rapid expansion rate in high-latitude China demonstrated a higher risk of potential invasion in the north;dynamic monitoring and control management should be established as soon as possible.展开更多
The castings defects are affected by the melting volume change rate of material. The change rate has an important effect on running safety of the high temperature thermal storage chamber, too. But the characteristics ...The castings defects are affected by the melting volume change rate of material. The change rate has an important effect on running safety of the high temperature thermal storage chamber, too. But the characteristics of existing measuring installations are complex structure, troublesome operation and low precision. In order to measure the melting volume change rate of material accurately and conveniently, a self-designed measuring instrument, self-heating probe instrument, and measuring method are described. Temperature in heating cavity is controlled by PID temperature controller; melting volume change rate υ and molten density are calculated based on the melt volume which is measured by the instrument. Positive and negative υ represent expansion and shrinkage of the sample volume after melting, respectively. Taking eutectic LiF+CaF2 for example, its melting volume change rate and melting density at 1 123 K are -20.6% and 2 651 kg/m–3 measured by this instrument, which is only 0.71% smaller than literature value. Density and melting volume change rate of industry pure aluminum at 973 K and analysis pure NaCl at 1 123 K are detected by the instrument too. The measure results are agreed with report values. Measuring error sources are analyzed and several improving measures are proposed. In theory, the measuring errors of the change rate and molten density which are measured by the self-designed instrument is nearly 1/20-1/50 of that measured by the refitted mandril thermal expansion instrument. The self-designed instrument and method have the advantages of simple structure, being easy to operate, extensive applicability for material, relatively high accuracy, and most importantly, temperature and sample vapor pressure have little effect on the measurement accuracy. The presented instrument and method solve the problems of complicated structure and procedures, and large measuring errors for the samples with high vapor pressure by existing installations.展开更多
The research used industrial by-products original phosphogypsum(PG)as the main raw material,slag(SG)and Portland cement(PC)as auxiliary materials,and the optimal additive amount was determined according to the compres...The research used industrial by-products original phosphogypsum(PG)as the main raw material,slag(SG)and Portland cement(PC)as auxiliary materials,and the optimal additive amount was determined according to the compressive strength value of the sample.Comprehensively evaluate the water resistance and volume stability of the samples,and determine the best formula for new roadbed stabilized materials.The results showed that when the weight ratio of PG,slag and cement was OPG:SG:PC=6:3:1,and mixed with 5%micro silica fume(MSF)and 3‰hydroxypropyl methyl cellulose(HPMC),the sample’s comprehensive performance was the best,specifically,the sample’s compressive strength in 60 days reached 28.8 MPa,the softening coefficient reached 0.9,and the expansion rate was stable at about−0.2%.In addition,the mechanism of action of enhancers MSF and HPMC was analyzed according to use Vicat device,X-ray diffractometer and scanning electron microscope.The best formula SP3GH3 has the best curing effect on soil.The 28-day unconfined compressive strength(UCS)of the sample reached 2.4 MPa,the expansion rate was less than 0.09%,and the water stability coefficient was above 0.79,which was higher than that of the samples cured by traditional cement and lime during the same period.展开更多
Salt expansion in sulfate saline soils that are widely distributed in northwestern China causes serious infrastructural damages under low-temperature conditions. However, the mechanism of salt expansion under low temp...Salt expansion in sulfate saline soils that are widely distributed in northwestern China causes serious infrastructural damages under low-temperature conditions. However, the mechanism of salt expansion under low temperatures is not clear. In this study, we conducted a series of cooling experiments combined with salt crystallization to study this mechanism, and employed an ionic model to calculate the supersaturation ratio of the solution. During the experiments, the strength and the process of salt expansion were examined under different cooling rates and various crystal morphologies. The relationship between temperature and supersaturation ratio under transient conditions was also considered. Results indicate that the initial supersaturation ratio of a sodium sulfate solution is closely related to environmental conditions, and that this ratio decreases with slowing the cooling rates and stabilizing the crystal forms. Higher initial supersaturation ratios lead to an increased non-steady-state zone, resulting in less salt expansion. On the other hand, chloride ion content has a distinct influence on the crystallization supersaturation ratio of the sodium sulfate solution, and higher chloride ion content can inhibit salt expansion in sodium saline soils. These findings help explain salt expansion mechanisms in complex conditions such as seasonally frozen soils, and thus help search for improved methods of preventing salt expansion in sulfate saline soils.展开更多
Qinghai Lake Basin area in Gangcha county is selected as the study area in terms of desertification change features in this paper.Based on the remote sensing(RS)and global positioning system(GPS)technologies,the deser...Qinghai Lake Basin area in Gangcha county is selected as the study area in terms of desertification change features in this paper.Based on the remote sensing(RS)and global positioning system(GPS)technologies,the desertification information range from 1989 to 2014 in the study area is extracted.Using the method of the decision tree,the desertification in the research area is been divided into four grades including mild desertification,moderate desertification,severe desertification and serious desertification.The change characteristics of desertification in the study area were analyzed in detail,which showed that the desertification in the study area experienced a process of first development and then a reversal.The rapid development of desertification appears in the 1990s,where about 1101.22 kilometers of desertification area was increased in this stage.Since the twenty-first Century,the desertification is gradually significant recovered and local area exist intensified desertification.There are tendencies of interactive transform in different types of desertification.The tendencies of different degrees of desertification land are rising,and there’re some differences in rising rates,where the expansion rate of moderate desertification is the biggest,increasing by 7.27 kilometers per year.展开更多
National and international policies have promoted quinoa consumption, influencing the expansion of the crop, and generating changes in land use. In this article, we analyzed the evolution of quinoa cultivation in Peru...National and international policies have promoted quinoa consumption, influencing the expansion of the crop, and generating changes in land use. In this article, we analyzed the evolution of quinoa cultivation in Peru both at the national and departmental levels. Time series analysis vas used to. Between 1951 and 2019, the evolution of the quinoa-harvested areas in Peru has gone through various stages, first in regression until 1990, and then it has experienced a growth rate of 10%. Puno is still by far the department where the crop is most widespread. Taking into account the geographical and technological conditions, this highland area is less likely to maintain the rate of expansion than the Peruvian coast, which will imply great challenges for Andean farmers who have maintained the traditional crop throughout the period.展开更多
Urban gullies are a rapidly growing concern in many tropical cities of the Global South.Various measures are already implemented for their stabilization.However,an overview of these measures and their overall effectiv...Urban gullies are a rapidly growing concern in many tropical cities of the Global South.Various measures are already implemented for their stabilization.However,an overview of these measures and their overall effectivenesss is currently lacking.We aim at addressing this gap by documenting existing ini-tiatives to stabilize urban gullies in D.R.Congo and assessing their overall effectiveness.To this end we conducted extensive field campaigns in Kinshasa,Kikwit and Bukavu and combined our terrain obser-vations with data on gully expansion rates(derived from series of satellite imagery).In total,we char-acterized present and past stabilization initiatives for 398 urban gullies.For 69 of these gullies,the effect of a specific measure on gully expansion rates could be estimated.Results show that for the large ma-jority of gullies,various measures have been implemented.Yet,these are mainly ad-hoc measures installed by the affected population.More structural measures based on larger engineering works were observed for only 20-30%of gullies.The huge efforts invested in the installation of measures strongly contrast with their overall low impact Among all strategies,only the deviation of runoff resulted in significantly lower expansion rates after installation.The numerous initiatives that rely on the sparse means available seem to have limited effects.This does not imply,however,that they are completely ineffective and should be abandoned.Based on our findings,we formulate recommendations for further research on how to effectively prevent and stabilize urban gullies,taking into account the difficult environmental and socio-economic context.展开更多
Gas wiping is a decisive operation in hot-dip galvanizing process. In special, it has a crucial influence on the thickness and uniformity in coating film, but may be subsequently responsible for the problem of splashi...Gas wiping is a decisive operation in hot-dip galvanizing process. In special, it has a crucial influence on the thickness and uniformity in coating film, but may be subsequently responsible for the problem of splashing. The progress of industry demands continuously the reduction of production costs which may relate directly with the increase of coating speed, and the speed up of coating results in the increase of stagnation pressure in gas wiping system in final. It is known that the increase of stagnation pressure may accompany a harmful problem of splashing in general. Together with these, also, from the view point of energy consumption, it is necessary to design a nozzle optimally. And there is known that the downward tilting of nozzle using in air knife system is effective to prevent in somewhat the harmful problem of splashing. In these connections, first, we design a nozzle with constant expansion rate. Next, for the case of actual coating conditions in field, the effects of tilting of the constant expansion rate nozzle are investigated by numerical analysis. Under the present numerical conditions, it was turned out that the nozzle of constant expansion rate of p = having a downward jet angle of 5^0 is the most effective to diminish the onset of splashing, while the influence of small tilting of the nozzle on impinging wall pres- sure itself is not so large.展开更多
Navigation with sensor networks has shown many advantages and great potential in many scenarios. Previous works have mainly focused on selecting the shortest path to navigate an internal user out of an emergency field...Navigation with sensor networks has shown many advantages and great potential in many scenarios. Previous works have mainly focused on selecting the shortest path to navigate an internal user out of an emergency field. However, they did not consider variations of the dangerous areas which usually occur in practical applications. This paper presents an efficient dynamic routing algorithm to successfully guide users to the destination exit. The navigation goal is looking for a safe and short path to enable the user to escape from a dangerous area as fast as possible. Without knowing the locations of the nodes, the user is guided by a sequence of sensor nodes to pass through the dangerous areas. The algorithm ensures the navigation path security by predicting the dynamic changes affecting the navigation path. The performance of this approach is evaluated using extensive simulations to validate its effectiveness. Simulations show that the approach is scalable and performs well in various settings.展开更多
文摘This paper suggests explanations for otherwise seemingly unexplained data about elementary particles and cosmology. The explanations have bases in coordinate-based modeling and in integer-based characterizations for some catalogs. One catalog features properties—including charge, mass, and angular momentum—of objects. Another catalog features all known and some possible elementary particles. Assumptions include that multipole-expansion mathematics has uses regarding long-range interactions, such as gravity, and that nature includes six isomers of all elementary particles other than long-range-interaction bosons. One isomer associates with ordinary matter. Five isomers are associated with dark matter. Multipole notions help explain large-scale aspects such as the rate of expansion of the universe.
基金Under the auspices of Special Foundation for State Major Basic Research Program of China(No.2013FY111800,2013FY111100-02)
文摘Biological invasion poses a huge threat to ecological security.Spartina alterniflora was introduced into China in 1979,and its arrival corresponded with negative effects on native ecosystems.To explore geographical variation of its expansion rate in coastal China,we selected 43 S.alterniflora sites from Tianjin Coastal New Area to Beihai.The area expansion rate,expansion rate paralleling and vertical to the shoreline were analysed based on Landsat images and field survey in 2015.Simple Ocean Data Assimilation(SODA)and climate data were collected to statistically analyse the influential factors of expansion rate.Results showed that significant difference of S.alterniflora area expansion rate among different latitude zones(P<0.01),increasing from 6.08%at southern(21°N–23°N)to 19.87% in Bohai Bay(37°N–39°N)along latitude gradient.There was a significant difference in expansion rate vertical to shoreline in different latitude zones(P<0.01)with the largest occurring in Bohai Bay(256m/yr,37°N–39°N),and showed an decreasing tendency gradually from north to south.No significant difference and latitudinal clines in expansion rate paralleling to shoreline were observed.Expansion rate had significant negative correlation with mean seawater temperature,the lowest seawater temperature,current zonal velocity and meridional velocity and presented a reducing trend as these biotic factors increased;however,they were not significantly correlated with the highest seawater temperature and mean seawater salinity.We identified significant correlations between expansion rate and annual mean temperature,the lowest temperature in January and annual precipitation,but there was little correlation with annual diurnal difference in temperature and the highest temperature in July.The rapid expansion rate in high-latitude China demonstrated a higher risk of potential invasion in the north;dynamic monitoring and control management should be established as soon as possible.
基金supported by Gansu Provincial Critical Patented Projects of China(Grant No. 1101ZSB117)Gansu Provincial Science and Technology Pillar Program of China(Grant No. 1002ZSB018)
文摘The castings defects are affected by the melting volume change rate of material. The change rate has an important effect on running safety of the high temperature thermal storage chamber, too. But the characteristics of existing measuring installations are complex structure, troublesome operation and low precision. In order to measure the melting volume change rate of material accurately and conveniently, a self-designed measuring instrument, self-heating probe instrument, and measuring method are described. Temperature in heating cavity is controlled by PID temperature controller; melting volume change rate υ and molten density are calculated based on the melt volume which is measured by the instrument. Positive and negative υ represent expansion and shrinkage of the sample volume after melting, respectively. Taking eutectic LiF+CaF2 for example, its melting volume change rate and melting density at 1 123 K are -20.6% and 2 651 kg/m–3 measured by this instrument, which is only 0.71% smaller than literature value. Density and melting volume change rate of industry pure aluminum at 973 K and analysis pure NaCl at 1 123 K are detected by the instrument too. The measure results are agreed with report values. Measuring error sources are analyzed and several improving measures are proposed. In theory, the measuring errors of the change rate and molten density which are measured by the self-designed instrument is nearly 1/20-1/50 of that measured by the refitted mandril thermal expansion instrument. The self-designed instrument and method have the advantages of simple structure, being easy to operate, extensive applicability for material, relatively high accuracy, and most importantly, temperature and sample vapor pressure have little effect on the measurement accuracy. The presented instrument and method solve the problems of complicated structure and procedures, and large measuring errors for the samples with high vapor pressure by existing installations.
基金This work was supported by the Jiangsu Provincial Science and Technology Department’s Social Development-Major Science and Technology Demonstration Project(Grant No.BE2018697)the Jiangsu Provincial Science and Technology Department Social Development Project(Grant No.BE2017704)the Scientific Research Project of the Suqian Municipal Transportation Bureau.
文摘The research used industrial by-products original phosphogypsum(PG)as the main raw material,slag(SG)and Portland cement(PC)as auxiliary materials,and the optimal additive amount was determined according to the compressive strength value of the sample.Comprehensively evaluate the water resistance and volume stability of the samples,and determine the best formula for new roadbed stabilized materials.The results showed that when the weight ratio of PG,slag and cement was OPG:SG:PC=6:3:1,and mixed with 5%micro silica fume(MSF)and 3‰hydroxypropyl methyl cellulose(HPMC),the sample’s comprehensive performance was the best,specifically,the sample’s compressive strength in 60 days reached 28.8 MPa,the softening coefficient reached 0.9,and the expansion rate was stable at about−0.2%.In addition,the mechanism of action of enhancers MSF and HPMC was analyzed according to use Vicat device,X-ray diffractometer and scanning electron microscope.The best formula SP3GH3 has the best curing effect on soil.The 28-day unconfined compressive strength(UCS)of the sample reached 2.4 MPa,the expansion rate was less than 0.09%,and the water stability coefficient was above 0.79,which was higher than that of the samples cured by traditional cement and lime during the same period.
基金supported by the National Natural Science Foundation of China (41601068, 31602001, 41230630)the Young Scholars Development Fund of Southwest Petroleum University (201599010104)the Scientific Research Starting Project of Southwest Petroleum University (2015QHZ025)
文摘Salt expansion in sulfate saline soils that are widely distributed in northwestern China causes serious infrastructural damages under low-temperature conditions. However, the mechanism of salt expansion under low temperatures is not clear. In this study, we conducted a series of cooling experiments combined with salt crystallization to study this mechanism, and employed an ionic model to calculate the supersaturation ratio of the solution. During the experiments, the strength and the process of salt expansion were examined under different cooling rates and various crystal morphologies. The relationship between temperature and supersaturation ratio under transient conditions was also considered. Results indicate that the initial supersaturation ratio of a sodium sulfate solution is closely related to environmental conditions, and that this ratio decreases with slowing the cooling rates and stabilizing the crystal forms. Higher initial supersaturation ratios lead to an increased non-steady-state zone, resulting in less salt expansion. On the other hand, chloride ion content has a distinct influence on the crystallization supersaturation ratio of the sodium sulfate solution, and higher chloride ion content can inhibit salt expansion in sodium saline soils. These findings help explain salt expansion mechanisms in complex conditions such as seasonally frozen soils, and thus help search for improved methods of preventing salt expansion in sulfate saline soils.
基金This work was supported by the National Natural Science Foundation of China“Study on the dynamic mechanism of grassland ecosystem response to climate change in Qinghai Plateau”under grant number U20A2098.
文摘Qinghai Lake Basin area in Gangcha county is selected as the study area in terms of desertification change features in this paper.Based on the remote sensing(RS)and global positioning system(GPS)technologies,the desertification information range from 1989 to 2014 in the study area is extracted.Using the method of the decision tree,the desertification in the research area is been divided into four grades including mild desertification,moderate desertification,severe desertification and serious desertification.The change characteristics of desertification in the study area were analyzed in detail,which showed that the desertification in the study area experienced a process of first development and then a reversal.The rapid development of desertification appears in the 1990s,where about 1101.22 kilometers of desertification area was increased in this stage.Since the twenty-first Century,the desertification is gradually significant recovered and local area exist intensified desertification.There are tendencies of interactive transform in different types of desertification.The tendencies of different degrees of desertification land are rising,and there’re some differences in rising rates,where the expansion rate of moderate desertification is the biggest,increasing by 7.27 kilometers per year.
文摘National and international policies have promoted quinoa consumption, influencing the expansion of the crop, and generating changes in land use. In this article, we analyzed the evolution of quinoa cultivation in Peru both at the national and departmental levels. Time series analysis vas used to. Between 1951 and 2019, the evolution of the quinoa-harvested areas in Peru has gone through various stages, first in regression until 1990, and then it has experienced a growth rate of 10%. Puno is still by far the department where the crop is most widespread. Taking into account the geographical and technological conditions, this highland area is less likely to maintain the rate of expansion than the Peruvian coast, which will imply great challenges for Andean farmers who have maintained the traditional crop throughout the period.
文摘Urban gullies are a rapidly growing concern in many tropical cities of the Global South.Various measures are already implemented for their stabilization.However,an overview of these measures and their overall effectivenesss is currently lacking.We aim at addressing this gap by documenting existing ini-tiatives to stabilize urban gullies in D.R.Congo and assessing their overall effectiveness.To this end we conducted extensive field campaigns in Kinshasa,Kikwit and Bukavu and combined our terrain obser-vations with data on gully expansion rates(derived from series of satellite imagery).In total,we char-acterized present and past stabilization initiatives for 398 urban gullies.For 69 of these gullies,the effect of a specific measure on gully expansion rates could be estimated.Results show that for the large ma-jority of gullies,various measures have been implemented.Yet,these are mainly ad-hoc measures installed by the affected population.More structural measures based on larger engineering works were observed for only 20-30%of gullies.The huge efforts invested in the installation of measures strongly contrast with their overall low impact Among all strategies,only the deviation of runoff resulted in significantly lower expansion rates after installation.The numerous initiatives that rely on the sparse means available seem to have limited effects.This does not imply,however,that they are completely ineffective and should be abandoned.Based on our findings,we formulate recommendations for further research on how to effectively prevent and stabilize urban gullies,taking into account the difficult environmental and socio-economic context.
文摘Gas wiping is a decisive operation in hot-dip galvanizing process. In special, it has a crucial influence on the thickness and uniformity in coating film, but may be subsequently responsible for the problem of splashing. The progress of industry demands continuously the reduction of production costs which may relate directly with the increase of coating speed, and the speed up of coating results in the increase of stagnation pressure in gas wiping system in final. It is known that the increase of stagnation pressure may accompany a harmful problem of splashing in general. Together with these, also, from the view point of energy consumption, it is necessary to design a nozzle optimally. And there is known that the downward tilting of nozzle using in air knife system is effective to prevent in somewhat the harmful problem of splashing. In these connections, first, we design a nozzle with constant expansion rate. Next, for the case of actual coating conditions in field, the effects of tilting of the constant expansion rate nozzle are investigated by numerical analysis. Under the present numerical conditions, it was turned out that the nozzle of constant expansion rate of p = having a downward jet angle of 5^0 is the most effective to diminish the onset of splashing, while the influence of small tilting of the nozzle on impinging wall pres- sure itself is not so large.
基金Supported by the National Key Basic Research and Development Program (973) of China (No. 2011CB302705)in part by the Zhejiang Agriculture & Forest University Innovation (No. 2009RC11)+1 种基金Science Technology Department of Zhejiang Province Commonwealth (No. 2011C31G2100015)the Zhejiang Provincial Natural Science Foundation (Nos. Y3090558 and Y3100363)
文摘Navigation with sensor networks has shown many advantages and great potential in many scenarios. Previous works have mainly focused on selecting the shortest path to navigate an internal user out of an emergency field. However, they did not consider variations of the dangerous areas which usually occur in practical applications. This paper presents an efficient dynamic routing algorithm to successfully guide users to the destination exit. The navigation goal is looking for a safe and short path to enable the user to escape from a dangerous area as fast as possible. Without knowing the locations of the nodes, the user is guided by a sequence of sensor nodes to pass through the dangerous areas. The algorithm ensures the navigation path security by predicting the dynamic changes affecting the navigation path. The performance of this approach is evaluated using extensive simulations to validate its effectiveness. Simulations show that the approach is scalable and performs well in various settings.