The researches on the assessment of earthquake forecast are reviewed, then the R-value assessment is further developed theoretically in the paper. The results include the arithmetic of the R-values of earthquake occur...The researches on the assessment of earthquake forecast are reviewed, then the R-value assessment is further developed theoretically in the paper. The results include the arithmetic of the R-values of earthquake occurrence under the condition that 'anomaly' occurred or no 'anomaly' occurred respectively, and the relation between the values. The distribution of Rvalue of a forecast method, corresponding to multi-status anomalies being independent each other, is also developed in the paper. The appropriate methods to estimate the R-values and extrapolate the occurrence probability of future earthquakes are also given in the paper.展开更多
Based on the experimental data,it was clarified that the plastic strain ratio R-value is not equal to Hill's r-value for Ti sheet.From the non-quadratic orthotropic yield function pro- posed recently by the author...Based on the experimental data,it was clarified that the plastic strain ratio R-value is not equal to Hill's r-value for Ti sheet.From the non-quadratic orthotropic yield function pro- posed recently by the author,an optimal expression between yield stress and r-value for Ti sheet was developed on overall investigation.The suitable value of exponent in the function seems to be 6—8.Thus,an equation was suggested to estimate strength for the pressure vessel made of Ti sheet.展开更多
An attempt was made on the quantitative prediction of the relationship hetween the yield stress and R-value along the parallel and perpendicular to the rolling direction of Ti plate based on analysis of the previous e...An attempt was made on the quantitative prediction of the relationship hetween the yield stress and R-value along the parallel and perpendicular to the rolling direction of Ti plate based on analysis of the previous experimental data.It is shown that the yield stress along one direction and another is quite synchronized with the R—value.According to the plasticity theo- ry,an formular of σ_(1s)/σ_(2s)=[(1+1/R_2)/(1+1/R_1)/^(1 2) was proposed,In statistic estima- tion.the calculated results are in good agreement with the experimental data.The availability of this formula was briefly discussed also.展开更多
Establishing a quantitative relationship between modern pollen and vegetation remains a pivotal but intricate pursuit within the field of Quaternary palynology.The R-value,a well-established and traditional metric cha...Establishing a quantitative relationship between modern pollen and vegetation remains a pivotal but intricate pursuit within the field of Quaternary palynology.The R-value,a well-established and traditional metric characterized by its simplicity and direct applicability,serves to calibrate the nonlinear disparities between surface pollen and modern vegetation.This study entails the construction of a comprehensive pollen R-value dataset for China derived from R-values published between 1987 and 2021.The dataset,compiled after rigorous screening,calibration,and standardization processes,encompasses 898 modern pollen sampling sites and 2115 pollen R-value data entries,encapsulating 152 pollen taxa spanning 65 families and 113 genera.Synthesizing the extracted R-values yielded the following insights:(1)A macrospatial analysis validates previously established knowledge at a site-specific scale.Evidently,pollen R-value variations across China are statistically significant.Approximately two-thirds of pollen taxa exhibit underrepresentation(e.g.,Taxodiaceae,Corylus,Nitraria,Tamarix,Cyperaceae,Poaceae,and Fabaceae),while the remaining one-third display overrepresentation(e.g.,Pinus,Picea,Betula,Ephedra,Chenopodiaceae,and Artemisia).The degree of underrepresentation surpasses that of overrepresentation,and the representation patterns of Castanea,Quercus,Polygonaceae,and Asteraceae are contingent upon vegetation types.(2)Pollen R-values follow distinct spatial distribution patterns within China.In the woody vegetation region of eastern China,R-values progressively decline from north to south,correlating with rising temperatures and precipitation.Conversely,in herbaceous vegetation regions of northern and western China,R-values decrease from east to west and from northeast to southwest,corresponding to increased aridity.Nevertheless,pollen R-values manifest variation contingent on pollen taxa,vegetation types,and climatic regions,even differing for the same taxa across varying vegetation types and climatic conditions.This highlights the intricate nature of pollen R-values and their interpretation of pollen-vegetation relationships.(3)Pollen R-values and relative pollen production estimates exhibit resemblances and a modest positive correlation.However,adjudicating between them as representatives of vegetation requires nuanced consideration,as both metrics convey pollen representation within vegetation,demonstrating the multifaceted relationships they share with modern vegetation.Further recommendations suggest that when assessing pollen representation in modern vegetation,fossil pollen content should be weighted using either the median or log-transformed R-value.This approach underscores the necessity of comprehensively accounting for divergences and convergences across various spatial scales and vegetation types,particularly the disparities observed within identical pollen taxa across dissimilar regions.展开更多
The Debao MS4.8 earthquake occurred in western Guangxi on August 5,2021,near where the Jingxi MS5.2 earthquake occurred in 2019.To study the increasing seismicity in western Guangxi,it is necessary to determine whethe...The Debao MS4.8 earthquake occurred in western Guangxi on August 5,2021,near where the Jingxi MS5.2 earthquake occurred in 2019.To study the increasing seismicity in western Guangxi,it is necessary to determine whether there was an anomaly related to the earthquake source near the Pingxiang gravity station,which is located approximately 100 km from the epicenter of the Debao MS4.8 earthquake.In this study,the R-value scoring method was used to analyze the anomaly and evaluate the prediction efficiency of the double frequency(DF)micro-seismic signal vertical displacement(referred to as vertical displacement,VD)and the absolute value of monthly extreme rate(referred to as the monthly rate).Results show that earthquakes larger than MS4.0 in the 350 km range from the Pingxiang station tend to coincide with yearly typhoons,and the VD of micro-seismic signals correspondingly changes from low to high.The Debao MS4.8 earthquake occurred during a gradual VD increase from 0.05×10^(-6)to 0.10×10^(-6)m.When discussing the relationships among R,the rate threshold,and the effective duration of prediction,the rate threshold of the micro-seismic signal converges from 0.00039×10^(-6)to 0.00031×10^(-6)m/month,the effective duration of prediction is approximately 6-10 months,and R also converges from 0.29 to 0.31.By comparing the results of three gPhone gravity stations in Guangxi,we found that the increase of short-term VD before the Debao earthquake was related to the enhancement of the DF micro-seismic signal excited by the typhoon.When the typhoon track was perpendicular to the coastline of China,the possibility of an earthquake occurring was increased.This study provides evidence and reference for the future occurrence period of earthquakes above MS4.0 in western Guangxi.展开更多
Two kinds of cold rolling experiments, single cold rolling and double cold rolling, were carried out on one titanium stabilized interstitial free (IF) steel that has been warm rolled at ferrite temperature. The main a...Two kinds of cold rolling experiments, single cold rolling and double cold rolling, were carried out on one titanium stabilized interstitial free (IF) steel that has been warm rolled at ferrite temperature. The main aim was to investigate the evolution of rolling and annealing textures from the well known behavior observed under single cold rolling condition to the less understood double cold rolling by using orientation distribution function (ODF). In the twice cold rolled samples, the annealing texture comprises only single {111}(110-112) r-fibre texture when it subjected to moderate reduction in the first round of rolling. Accordingly both the once cold rolled sample and the twice cold rolled sample with heavy reduction in the first round of rolling have much complex texture components. They are related to the formation of initial {111} subgrain and the priority growth of stable {111} nucleus.展开更多
A hot-rolled deep drawing(HDD)steel with high r-value and uniformdistribution of{111}texture in thickness was developed by hot rolling in ferrite region withlubricating between the roller and the steel.The experimenta...A hot-rolled deep drawing(HDD)steel with high r-value and uniformdistribution of{111}texture in thickness was developed by hot rolling in ferrite region withlubricating between the roller and the steel.The experimental results show that the carbon contentand finish rolling temperature have significant effects on beneficial texture{111},and lubricatingduring hot rolling at low temperature in alpha-region makes the distribution of the textureuniform.Three basic requirements needed to meet for HDD steel were concluded by comparing differentcarbon contents and hot rolling processes.展开更多
The effect of stabilizing elements, such as Nb and Ti, on the microstructure and properties of low carbon ferritic stainless steel (FSS) has been investigated. The results of the Thermo-calc simulation have shown th...The effect of stabilizing elements, such as Nb and Ti, on the microstructure and properties of low carbon ferritic stainless steel (FSS) has been investigated. The results of the Thermo-calc simulation have shown that the interstitial elements, such as C and N, may be completely stabilized by the addition of Nb and Ti. With the increase of Nb and Ti contents ,the α + γ two phases gradually transfer to a single α-phase under a high temperature condition ,and the content of the carbide M23 C6 gradually decreases. The microstructure has indicated that the combined addition of Nb and Ti can promote the recrystallization of the band structure and form more uniform equiaxed grains. Also, with the increase of Nb and Ti contents,the elongation, the r-value and the corrosion resistance of cold-rolled and annealed sheets are improved prominently. In comparison with the effect of Ti ,the addition of Nb is more beneficial to the increase of r-value and the corrosion resistance.展开更多
Based on the pollen data obtained from thirty-five surface soil samples and investigated vegetation data from seven plant quadrats,the quantitative relationship between surface soil pollen and modern vegetation are st...Based on the pollen data obtained from thirty-five surface soil samples and investigated vegetation data from seven plant quadrats,the quantitative relationship between surface soil pollen and modern vegetation are studied in the longitudinal range-gorge region (LRGR) in Southwestern China.R-values (referring to pollen assemblages) are calculated with pollen percentage and plant abundance.The coefficients of similarity between pollen and vegetation are analyzed.The results show that the pollen assemblages on surface soil of all vegetation zones can basically represent the native vegetation,but the pollen assemblages are not fully according with the vegetation.This is due to the influencing factors including pollen preservation ability,pollen production,amount of exotic pollen and pollen identification.The pollen representation in surface soil is different in families and genera.The pollen of woody plants such as Pinus,Tsuga,Alnus,Fagus and Castanopsis are over-representative,but those of Quercus,Carpinus Myrica,Elaeocarpaceae,Ericaceae,Theaceae and Llex are underrepresentative;the pollen of herbaceous plants such as Artemisia and Rubiaceae are over-representative,while those of others including Gramineae and Araliaceae are under-representative.The R-values of the same taxon pollen in different vegetation zones are different,depending on their distances from the pollen sources.The coefficients of the similarity between plant communities and pollen assemblages are mostly over 70%,which indicate again that the surface soil pollen and spores assemblages can represent the vegetation.It is concluded that there is a good corresponding relationship between surface pollen assemblages and native vegetation in LRGR,and it is of great significance for reconstructing the past vegetation and paleoclimate using quantitative fossil pollen data in this region.展开更多
The principle of middle and long-term earthquake forecast model of spatial and temporal synthesized probability gain and the evaluation of forecast efficiency (R-values) of various forecast methods are introduced in t...The principle of middle and long-term earthquake forecast model of spatial and temporal synthesized probability gain and the evaluation of forecast efficiency (R-values) of various forecast methods are introduced in this paper. The R-value method, developed by Xu (1989), is further developed here, and can be applied to more complicated cases. Probability gains in spatial and/or temporal domains and the R-values for different forecast methods are estimated in North China. The synthesized probability gain is then estimated as an example.展开更多
The relationships among the deformation, texture and deep drawing properties of IF steel were investigated. By adopting double cold rolling (DCR) technology, the deep drawing property has been developed evidently. Wit...The relationships among the deformation, texture and deep drawing properties of IF steel were investigated. By adopting double cold rolling (DCR) technology, the deep drawing property has been developed evidently. With the aid of orientation distribution function (ODF) analysis, it was found that he main reason for good property is the counterbalance in intensity of the ideal texture component {111} < 011 > and {111} < 112 >.展开更多
Today,to describe the thermal performance of the building envelope and its components we use a variation of metrics;such as,R-value,ACH(air exchange rate per hour),SHGC(solar heat gain coefficient)of windows,U-factor ...Today,to describe the thermal performance of the building envelope and its components we use a variation of metrics;such as,R-value,ACH(air exchange rate per hour),SHGC(solar heat gain coefficient)of windows,U-factor etc.None of these performance indicators is meant to represent the overall thermal performance.In this paper,such a metric is introduced,the BEP(building envelope performance)value.Unlike the thermal resistance,typically expressed as an R-value,the BEP-value considers additional elements of heat transfer that affect the energy demand of the building because of exterior and interior(solar)thermal loads:conductive and radiant heat transfer,and air infiltration.To demonstrate BEP’s utility,validation studies were carried out by comparing the BEP-value to theoretical results using whole building energy simulation tools such as EnergyPlus and WUFI Plus.Results show that BEP calculations are comparable to calculations made using these simulation tools and that unlike other similar metrics,the BEP-value accounts for all heat transfer mechanisms that are relevant for the overall energy performance of the building envelope.The BEP-value thus allows comparing envelopes of buildings with different use types in a fair and realistic manner.展开更多
INTRODUCTION In cold climates,a large amount of heat is lost through windows during the winter.For instance,a double-pane window might allow as much as 10 times the amount of heat to leave a house compared to the same...INTRODUCTION In cold climates,a large amount of heat is lost through windows during the winter.For instance,a double-pane window might allow as much as 10 times the amount of heat to leave a house compared to the same area of a typical 2×6 wall.It makes sense to upgrade or insulate windows in order to improve the thermal envelope of a home,especially in an area with a long heating season;however,windows are a very expensive component of the building envelope to replace.Replacing a single window can cost several hundred to more than a thousand dollars;therefore,people often resort to cheaper methods to reduce heat loss,such as shutters or curtains.Others may already have high-performance windows,but want to reduce heat loss even further by placing movable insulation over their windows during the cold winter nights.To help guide these decisions,the Cold Climate Housing Research Center(CCHRC)in Fairbanks,Alaska,conducted a study of common window insulation methods and compared them in terms of thermal effectiveness,affordability,ease of installation,durability,functionality,and condensation resistance.The purpose of the study was to inform homeowners about the various advantages and disadvantages of different window treatments.As part of the research,CCHRC studied a variety of methods and windows in volunteers’homes to understand how the methods work in real-life situations.CCHRC also modeled the retrofit window treatments with Therm 6.3,a modeling program,to help explain more generally how they can help homeowners.展开更多
To date,much of the research on green roof technology has focused on the capacity for these systems to contribute to the cooling of buildings during summer months.The thermal performance of green roofs in cold climate...To date,much of the research on green roof technology has focused on the capacity for these systems to contribute to the cooling of buildings during summer months.The thermal performance of green roofs in cold climate conditions is critical to understanding the potential of these roofs to decrease energy use in buildings during winter.This paper compares the behavior of two green roof systems with that of a conventional built-up roof by making use of a novel hot box testing apparatus.The green roofs tested are classified as extensive systems.Each system included:a 3 mm thick styrene butadiene rubber waterproofing membrane,0.2 mm thick polyethylene slip sheet,a 76 mm thick extruded polystyrene insulation layer,2 mm thick filter fabric,a 51 mm drainage layer followed by a 2 mm thick filter cloth,either 100 mm or 150 mm growing medium,and a 25 mm thick wild flower vegetated mat.The conventional roof consisted of a 2 mm thick layer of Kraft™vapour retarder bonded with insulation adhesive,51 mm of isocyanurate insulation,25 mm of fibreboard,a three ply(2 mm)cold-applied built-up roof membrane,and a gravel ballast finish 51 mm thick.Each roof was subjected to temperatures between 0℃ and–25℃,while the temperature within the hot box was held at 21℃.The effect of vegetation on a green roof to reduce wind speeds or increase snow cover were not considered in this study.The power required,as well as the temperatures throughout each system at steady state conditions,were monitored for 5 hours.The data collected from thermal testing suggests that the R-value of green roofs with 100 mm or 150 mm thick layers of growing medium is 37%higher than a conventional roof when subjected to temperatures of 0℃ to–25℃.展开更多
The steels were rolled at 3 different finishing temperatures. The mechanical properties were tested by tensile tests. The results show that as finish rolling temperature decreases from 620 to 560 ℃ in ferrite region,...The steels were rolled at 3 different finishing temperatures. The mechanical properties were tested by tensile tests. The results show that as finish rolling temperature decreases from 620 to 560 ℃ in ferrite region,the deep drawability of ferritic-rolled P-added high strength IF steels is improved,and r value rises from 1.14 to 1.37. Finish rolling temperature (FT) has less influence on other mechanical properties,such as yield strength,tensile strength and elongation. Microstructures of hot rolled and annealed steel sheets and precipitates of annealed steel sheets were also analyzed.展开更多
基金a result of a project sponsored by the China Seismological Bureau (95-04-07-04-01).
文摘The researches on the assessment of earthquake forecast are reviewed, then the R-value assessment is further developed theoretically in the paper. The results include the arithmetic of the R-values of earthquake occurrence under the condition that 'anomaly' occurred or no 'anomaly' occurred respectively, and the relation between the values. The distribution of Rvalue of a forecast method, corresponding to multi-status anomalies being independent each other, is also developed in the paper. The appropriate methods to estimate the R-values and extrapolate the occurrence probability of future earthquakes are also given in the paper.
文摘Based on the experimental data,it was clarified that the plastic strain ratio R-value is not equal to Hill's r-value for Ti sheet.From the non-quadratic orthotropic yield function pro- posed recently by the author,an optimal expression between yield stress and r-value for Ti sheet was developed on overall investigation.The suitable value of exponent in the function seems to be 6—8.Thus,an equation was suggested to estimate strength for the pressure vessel made of Ti sheet.
文摘An attempt was made on the quantitative prediction of the relationship hetween the yield stress and R-value along the parallel and perpendicular to the rolling direction of Ti plate based on analysis of the previous experimental data.It is shown that the yield stress along one direction and another is quite synchronized with the R—value.According to the plasticity theo- ry,an formular of σ_(1s)/σ_(2s)=[(1+1/R_2)/(1+1/R_1)/^(1 2) was proposed,In statistic estima- tion.the calculated results are in good agreement with the experimental data.The availability of this formula was briefly discussed also.
基金This work was supported by the Strategic Priority Research Program of the Chinese Academy of Sciences(Grant Nos.XDB31030104,XDA19050103 and XDA2009000003).
文摘Establishing a quantitative relationship between modern pollen and vegetation remains a pivotal but intricate pursuit within the field of Quaternary palynology.The R-value,a well-established and traditional metric characterized by its simplicity and direct applicability,serves to calibrate the nonlinear disparities between surface pollen and modern vegetation.This study entails the construction of a comprehensive pollen R-value dataset for China derived from R-values published between 1987 and 2021.The dataset,compiled after rigorous screening,calibration,and standardization processes,encompasses 898 modern pollen sampling sites and 2115 pollen R-value data entries,encapsulating 152 pollen taxa spanning 65 families and 113 genera.Synthesizing the extracted R-values yielded the following insights:(1)A macrospatial analysis validates previously established knowledge at a site-specific scale.Evidently,pollen R-value variations across China are statistically significant.Approximately two-thirds of pollen taxa exhibit underrepresentation(e.g.,Taxodiaceae,Corylus,Nitraria,Tamarix,Cyperaceae,Poaceae,and Fabaceae),while the remaining one-third display overrepresentation(e.g.,Pinus,Picea,Betula,Ephedra,Chenopodiaceae,and Artemisia).The degree of underrepresentation surpasses that of overrepresentation,and the representation patterns of Castanea,Quercus,Polygonaceae,and Asteraceae are contingent upon vegetation types.(2)Pollen R-values follow distinct spatial distribution patterns within China.In the woody vegetation region of eastern China,R-values progressively decline from north to south,correlating with rising temperatures and precipitation.Conversely,in herbaceous vegetation regions of northern and western China,R-values decrease from east to west and from northeast to southwest,corresponding to increased aridity.Nevertheless,pollen R-values manifest variation contingent on pollen taxa,vegetation types,and climatic regions,even differing for the same taxa across varying vegetation types and climatic conditions.This highlights the intricate nature of pollen R-values and their interpretation of pollen-vegetation relationships.(3)Pollen R-values and relative pollen production estimates exhibit resemblances and a modest positive correlation.However,adjudicating between them as representatives of vegetation requires nuanced consideration,as both metrics convey pollen representation within vegetation,demonstrating the multifaceted relationships they share with modern vegetation.Further recommendations suggest that when assessing pollen representation in modern vegetation,fossil pollen content should be weighted using either the median or log-transformed R-value.This approach underscores the necessity of comprehensively accounting for divergences and convergences across various spatial scales and vegetation types,particularly the disparities observed within identical pollen taxa across dissimilar regions.
基金supported by grants from the Seismological Science and Technology Spark Program of China Seismological Bureau(grant number XH23026C)the National Natural Science Foundation of China(grant number41204058)。
文摘The Debao MS4.8 earthquake occurred in western Guangxi on August 5,2021,near where the Jingxi MS5.2 earthquake occurred in 2019.To study the increasing seismicity in western Guangxi,it is necessary to determine whether there was an anomaly related to the earthquake source near the Pingxiang gravity station,which is located approximately 100 km from the epicenter of the Debao MS4.8 earthquake.In this study,the R-value scoring method was used to analyze the anomaly and evaluate the prediction efficiency of the double frequency(DF)micro-seismic signal vertical displacement(referred to as vertical displacement,VD)and the absolute value of monthly extreme rate(referred to as the monthly rate).Results show that earthquakes larger than MS4.0 in the 350 km range from the Pingxiang station tend to coincide with yearly typhoons,and the VD of micro-seismic signals correspondingly changes from low to high.The Debao MS4.8 earthquake occurred during a gradual VD increase from 0.05×10^(-6)to 0.10×10^(-6)m.When discussing the relationships among R,the rate threshold,and the effective duration of prediction,the rate threshold of the micro-seismic signal converges from 0.00039×10^(-6)to 0.00031×10^(-6)m/month,the effective duration of prediction is approximately 6-10 months,and R also converges from 0.29 to 0.31.By comparing the results of three gPhone gravity stations in Guangxi,we found that the increase of short-term VD before the Debao earthquake was related to the enhancement of the DF micro-seismic signal excited by the typhoon.When the typhoon track was perpendicular to the coastline of China,the possibility of an earthquake occurring was increased.This study provides evidence and reference for the future occurrence period of earthquakes above MS4.0 in western Guangxi.
文摘Two kinds of cold rolling experiments, single cold rolling and double cold rolling, were carried out on one titanium stabilized interstitial free (IF) steel that has been warm rolled at ferrite temperature. The main aim was to investigate the evolution of rolling and annealing textures from the well known behavior observed under single cold rolling condition to the less understood double cold rolling by using orientation distribution function (ODF). In the twice cold rolled samples, the annealing texture comprises only single {111}(110-112) r-fibre texture when it subjected to moderate reduction in the first round of rolling. Accordingly both the once cold rolled sample and the twice cold rolled sample with heavy reduction in the first round of rolling have much complex texture components. They are related to the formation of initial {111} subgrain and the priority growth of stable {111} nucleus.
文摘A hot-rolled deep drawing(HDD)steel with high r-value and uniformdistribution of{111}texture in thickness was developed by hot rolling in ferrite region withlubricating between the roller and the steel.The experimental results show that the carbon contentand finish rolling temperature have significant effects on beneficial texture{111},and lubricatingduring hot rolling at low temperature in alpha-region makes the distribution of the textureuniform.Three basic requirements needed to meet for HDD steel were concluded by comparing differentcarbon contents and hot rolling processes.
基金funded by the CITIC-CBMM R & D Subject Foundation(2010-D046).
文摘The effect of stabilizing elements, such as Nb and Ti, on the microstructure and properties of low carbon ferritic stainless steel (FSS) has been investigated. The results of the Thermo-calc simulation have shown that the interstitial elements, such as C and N, may be completely stabilized by the addition of Nb and Ti. With the increase of Nb and Ti contents ,the α + γ two phases gradually transfer to a single α-phase under a high temperature condition ,and the content of the carbide M23 C6 gradually decreases. The microstructure has indicated that the combined addition of Nb and Ti can promote the recrystallization of the band structure and form more uniform equiaxed grains. Also, with the increase of Nb and Ti contents,the elongation, the r-value and the corrosion resistance of cold-rolled and annealed sheets are improved prominently. In comparison with the effect of Ti ,the addition of Nb is more beneficial to the increase of r-value and the corrosion resistance.
基金supported by the National Basic Research Program of China (2003CB415101)
文摘Based on the pollen data obtained from thirty-five surface soil samples and investigated vegetation data from seven plant quadrats,the quantitative relationship between surface soil pollen and modern vegetation are studied in the longitudinal range-gorge region (LRGR) in Southwestern China.R-values (referring to pollen assemblages) are calculated with pollen percentage and plant abundance.The coefficients of similarity between pollen and vegetation are analyzed.The results show that the pollen assemblages on surface soil of all vegetation zones can basically represent the native vegetation,but the pollen assemblages are not fully according with the vegetation.This is due to the influencing factors including pollen preservation ability,pollen production,amount of exotic pollen and pollen identification.The pollen representation in surface soil is different in families and genera.The pollen of woody plants such as Pinus,Tsuga,Alnus,Fagus and Castanopsis are over-representative,but those of Quercus,Carpinus Myrica,Elaeocarpaceae,Ericaceae,Theaceae and Llex are underrepresentative;the pollen of herbaceous plants such as Artemisia and Rubiaceae are over-representative,while those of others including Gramineae and Araliaceae are under-representative.The R-values of the same taxon pollen in different vegetation zones are different,depending on their distances from the pollen sources.The coefficients of the similarity between plant communities and pollen assemblages are mostly over 70%,which indicate again that the surface soil pollen and spores assemblages can represent the vegetation.It is concluded that there is a good corresponding relationship between surface pollen assemblages and native vegetation in LRGR,and it is of great significance for reconstructing the past vegetation and paleoclimate using quantitative fossil pollen data in this region.
文摘The principle of middle and long-term earthquake forecast model of spatial and temporal synthesized probability gain and the evaluation of forecast efficiency (R-values) of various forecast methods are introduced in this paper. The R-value method, developed by Xu (1989), is further developed here, and can be applied to more complicated cases. Probability gains in spatial and/or temporal domains and the R-values for different forecast methods are estimated in North China. The synthesized probability gain is then estimated as an example.
基金This work was supported by the National Natural Science Foundation of China under Grant No.59995440 and by the State Ministry of Science and Technology of China, the High Technology Development Plan (863) Project No.2001AA332020.
文摘The relationships among the deformation, texture and deep drawing properties of IF steel were investigated. By adopting double cold rolling (DCR) technology, the deep drawing property has been developed evidently. With the aid of orientation distribution function (ODF) analysis, it was found that he main reason for good property is the counterbalance in intensity of the ideal texture component {111} < 011 > and {111} < 112 >.
基金This manuscript has been authored by UT-Battelle LLC under contract DE-AC05-00OR22725 with the US DOE(Department of Energy).
文摘Today,to describe the thermal performance of the building envelope and its components we use a variation of metrics;such as,R-value,ACH(air exchange rate per hour),SHGC(solar heat gain coefficient)of windows,U-factor etc.None of these performance indicators is meant to represent the overall thermal performance.In this paper,such a metric is introduced,the BEP(building envelope performance)value.Unlike the thermal resistance,typically expressed as an R-value,the BEP-value considers additional elements of heat transfer that affect the energy demand of the building because of exterior and interior(solar)thermal loads:conductive and radiant heat transfer,and air infiltration.To demonstrate BEP’s utility,validation studies were carried out by comparing the BEP-value to theoretical results using whole building energy simulation tools such as EnergyPlus and WUFI Plus.Results show that BEP calculations are comparable to calculations made using these simulation tools and that unlike other similar metrics,the BEP-value accounts for all heat transfer mechanisms that are relevant for the overall energy performance of the building envelope.The BEP-value thus allows comparing envelopes of buildings with different use types in a fair and realistic manner.
基金the Alaska Housing Finance Corporation,who provided the funding for this project.
文摘INTRODUCTION In cold climates,a large amount of heat is lost through windows during the winter.For instance,a double-pane window might allow as much as 10 times the amount of heat to leave a house compared to the same area of a typical 2×6 wall.It makes sense to upgrade or insulate windows in order to improve the thermal envelope of a home,especially in an area with a long heating season;however,windows are a very expensive component of the building envelope to replace.Replacing a single window can cost several hundred to more than a thousand dollars;therefore,people often resort to cheaper methods to reduce heat loss,such as shutters or curtains.Others may already have high-performance windows,but want to reduce heat loss even further by placing movable insulation over their windows during the cold winter nights.To help guide these decisions,the Cold Climate Housing Research Center(CCHRC)in Fairbanks,Alaska,conducted a study of common window insulation methods and compared them in terms of thermal effectiveness,affordability,ease of installation,durability,functionality,and condensation resistance.The purpose of the study was to inform homeowners about the various advantages and disadvantages of different window treatments.As part of the research,CCHRC studied a variety of methods and windows in volunteers’homes to understand how the methods work in real-life situations.CCHRC also modeled the retrofit window treatments with Therm 6.3,a modeling program,to help explain more generally how they can help homeowners.
文摘To date,much of the research on green roof technology has focused on the capacity for these systems to contribute to the cooling of buildings during summer months.The thermal performance of green roofs in cold climate conditions is critical to understanding the potential of these roofs to decrease energy use in buildings during winter.This paper compares the behavior of two green roof systems with that of a conventional built-up roof by making use of a novel hot box testing apparatus.The green roofs tested are classified as extensive systems.Each system included:a 3 mm thick styrene butadiene rubber waterproofing membrane,0.2 mm thick polyethylene slip sheet,a 76 mm thick extruded polystyrene insulation layer,2 mm thick filter fabric,a 51 mm drainage layer followed by a 2 mm thick filter cloth,either 100 mm or 150 mm growing medium,and a 25 mm thick wild flower vegetated mat.The conventional roof consisted of a 2 mm thick layer of Kraft™vapour retarder bonded with insulation adhesive,51 mm of isocyanurate insulation,25 mm of fibreboard,a three ply(2 mm)cold-applied built-up roof membrane,and a gravel ballast finish 51 mm thick.Each roof was subjected to temperatures between 0℃ and–25℃,while the temperature within the hot box was held at 21℃.The effect of vegetation on a green roof to reduce wind speeds or increase snow cover were not considered in this study.The power required,as well as the temperatures throughout each system at steady state conditions,were monitored for 5 hours.The data collected from thermal testing suggests that the R-value of green roofs with 100 mm or 150 mm thick layers of growing medium is 37%higher than a conventional roof when subjected to temperatures of 0℃ to–25℃.
基金Item Sponsored by Foundation for Outstanding Young Scientist in Shandong Province of China (9925)
文摘The steels were rolled at 3 different finishing temperatures. The mechanical properties were tested by tensile tests. The results show that as finish rolling temperature decreases from 620 to 560 ℃ in ferrite region,the deep drawability of ferritic-rolled P-added high strength IF steels is improved,and r value rises from 1.14 to 1.37. Finish rolling temperature (FT) has less influence on other mechanical properties,such as yield strength,tensile strength and elongation. Microstructures of hot rolled and annealed steel sheets and precipitates of annealed steel sheets were also analyzed.