The production and utilization of high-energetic explosives often pose a range of safety hazards,with sensitivity being a key factor in evaluating these risks.To investigate how temperature,particle size,and air humid...The production and utilization of high-energetic explosives often pose a range of safety hazards,with sensitivity being a key factor in evaluating these risks.To investigate how temperature,particle size,and air humidity affect the responsiveness of commonly used high-energetic explosives,a series of BAM(Bundesanstalt für Materialforschung und-prüfung)impact and friction sensitivity tests were carried out to determine the critical impact energy and critical load pressure of four representative high-energetic explosives(RDX,HMX,PETN and CL-20)under different temperatures,particle sizes,and air humidity conditions.The experimental findings facilitated an examination of temperature and particle size affecting the sensitivity of high-energetic explosives,along with an assessment of the influence of air humidity on sensitivity testing.The results clearly indicate that high-energetic explosives display a substantial decline in critical reaction energy when subjected to micrometre-sized particles and an air humidity level of 45%at a temperature of 90℃.Furthermore,it was noted that the critical reaction energy of high-energetic explosives diminishes with an increase in temperature within 25℃−90℃.In the same vein,as the particle sizes of high-energetic explosives increase,so does the critical reaction energy for micrometre-sized particles.High air humidity significantly affects the sensitivity testing of high-energetic explosives,emphasizing the importance of refraining from conducting sensitivity tests in such conditions.展开更多
The objective of this study is to quantify the values of greenhouse gases(GHGs) exchange in carbon equivalents of marshes and paddy fields in the Sanjiang Plain,Heilongjiang Province,China. We obtained the GHGs exchan...The objective of this study is to quantify the values of greenhouse gases(GHGs) exchange in carbon equivalents of marshes and paddy fields in the Sanjiang Plain,Heilongjiang Province,China. We obtained the GHGs exchange values based on comparable price by calculating the carbon sequestration values and the GHGs emission values of marshes and paddy fields respectively in four periods of 1982,1995,2000 and 2005. It is noted that the GHGs emission values are always negative. In this study,the marshes areas decreased from 1438977.0 to 775,132.2ha and the paddy fields areas increased from 417195.8 to 934205.0ha. The values of GHGs exchange of marshes varied from 135877.156×106 to 136882.534×106 yuan(RMB) and those of paddy fields varied from 1006.256×106 to 2767.645×106 yuan. The GHGs exchange values of marshes decreased from 1982 to 2005 on the whole,reversely,those of paddy fields increased,but those in 2005 were lower than those in 2000. In different periods,the GHGs exchange values were always higher in marshes than in paddy fields. The contribution rate of GHGs exchange values per unit area of marshes was also very high in different periods,and the maximum was up to 98.35% in 2005. As far as the whole wetland ecosystem(including marshes and paddy fields) ,assuming a linear change in GHGs exchange values,it represented a cumulative increase of 20926.757×106 yuan from 1982 to 2005. By adding GHGs exchange values increased during those four periods,we obtained a cumulative net increase values of GHGs exchange of wetland ecosystem of 18200.860×106 yuan. The results will be useful for understanding the indirect services provided by marshes and paddy fields.展开更多
The regional observed temperature and precipitation changes and their abruptjumps disturbed by large-scale reclamation in the Sanjiang Plain, Northeast China were studied. Meanannual temperature of the region was tend...The regional observed temperature and precipitation changes and their abruptjumps disturbed by large-scale reclamation in the Sanjiang Plain, Northeast China were studied. Meanannual temperature of the region was tending to go up and has increased by 1.2-2.2℃ over the past50 years. A warming jump of mean annual temperature of the region occurred in the 1980s, which hadan increasg amplitude of 0.9℃. Linear tendency rates of annual precipitation were negative in mostof the region. The maximum of annual precipitation decrease was 155.8mm over the past 50 years. Anabrupt decrease of regional annual precipitation happened in the middle of the 1960s, which had adecrease of 102.1mm. Based on the fact of climatic change of the Sanjiang Plain over the past 50years, it is held that the region had larger warming amplitude than that of the surrounding areas inthe recent years, which resulted from the large-scale reclamation of various kinds of wetlands.展开更多
Using monthly precipitation and monthly mean temperature, a surface humid index was proposed. According to the index, the distributed characteristics of extreme dryness has been fully analyzed. The results indicated t...Using monthly precipitation and monthly mean temperature, a surface humid index was proposed. According to the index, the distributed characteristics of extreme dryness has been fully analyzed. The results indicated that there is an obvious increasing trend of extreme dryness in the central part of northern China and northeastern China in the last 10 years, which shows a high frequency period of extreme dryness; while a low frequency period in the regions during the last 100 years. Compared with variation trend of the temperature in these regions, the region of high frequent extreme dryness is consistent with the warming trend in the same region.展开更多
This study aimed to conduct statistical analysis of temperature,relative humidity,wind direction,wind velocity,deep ground temperature and other related data from National Meteorological Observing Station of Hejian Ci...This study aimed to conduct statistical analysis of temperature,relative humidity,wind direction,wind velocity,deep ground temperature and other related data from National Meteorological Observing Station of Hejian City in 2012.According to the results,observation data varied due to different instruments and equipments,surrounding environments and underlying surface properties.The difference value of monthly average temperature between new site and old site ranged from-0.5 to 0 ℃; the difference value of monthly average maximum temperature ranged from-0.4 to 0.2 ℃; the difference value of monthly average minimum temperature ranged from-0.8 to 0 ℃; the difference value of monthly extreme maximum temperature ranged from-1.1 to 0.6 ℃; the difference value of monthly extreme minimum temperature ranged from-1.2 to 0.3 ℃.Annual average temperature,annual average maximum temperature and annual average minimum temperature in new site were lower than those in old site; annual extreme maximum temperature in new site was higher than that in old site; annual extreme minimum temperature in new site was lower than that in old site.The difference value of monthly average relative humidity between new site and old site ranged from 2% to 6%; the difference value of monthly minimum relative humidity ranged from-4% to 5%.Annual minimum relative humidity in new site was consistent with that in old site.The difference value of 2 min average wind velocity between new site and old site ranged from-0.1 to 0.4 m/s; the difference value of monthly maximum wind velocity ranged from-1.2 to 2.2 m/s; the difference value of monthly extreme wind velocity ranged from-2.0 to 2.8 m/s.Annual maximum wind velocity in new site was basically consistent with that in old site; annual extreme wind velocity in new site was significantly higher than that in old site; annual wind direction frequency in new site was lower than that in old site; annual most frequent wind direction in new site was S and that in old site was SSW.The difference value of average temperature at the depth of 40 cm ranged from-1.1 to 2.5 ℃; the difference value of average temperature at the depth of 80 cm ranged from-2.4 to 2.1 ℃; the difference value of average temperature at the depth of 160 cm ranged from-2.5 to 2.7 ℃; the difference value of average temperature at the depth of 320 cm ranged from-1.6 to 1.1 ℃.Annual average temperatures at the depths of 40 and 160 cm in new site were higher than those in old site,while annual average temperatures at the depths of 80 and 320 cm in new site were lower than those in old site.This paper provided certain correction stand for the use of observation data from new and old sites.展开更多
Humidification is an important step in humid air turbine system. The calculation on humidification is carried out at 423.15—573.15K, 5—15MPa. The results suggest that to produce high-enthalpy moist air, high water t...Humidification is an important step in humid air turbine system. The calculation on humidification is carried out at 423.15—573.15K, 5—15MPa. The results suggest that to produce high-enthalpy moist air, high water temperature and large water flow are needed. The water temperature is the most sensitive parameter to the humidification tower. And it is better for the humidification tower to work at temperature higher than 523 K when the system pressure is higher than 5 MPa. The comparison between the model used in this paper and ideal model shows that the ideal model can be used in simulation to simply the calculation when the temperature is lower than 473 K and pressure is lower than 5 MPa.展开更多
The results from three methods aimed at improving precipitation type (e.g., rain, sleet, and snow) estimation are presented and compared in this paper. The methods include the threshold air temperature (AT), thres...The results from three methods aimed at improving precipitation type (e.g., rain, sleet, and snow) estimation are presented and compared in this paper. The methods include the threshold air temperature (AT), threshold wet bulb temperature (WBT) and Koistinen and Saltikoff (KSS) methods. Dot graphs are plotted to acquire the threshold air temperature or the threshold wet bulb temperature using daily averaged air temperature, wet bulb temperature and precipitation data at 643 stations from 1961 to 1979 (precipitation types are not labeled in the database from 1980 to present) in China. The results indicate that the threshold AT or WBT methods are not able to differentiate rain, sleet and snow in the most regions in China; sleet is difficult to differentiate from other precipitation types based on the two threshold methods. Therefore, one threshold AT and WBT method was used in this study to differentiate rain and snow. Based on Gaussian- Kriging interpolation of threshold air temperature (To) and wet bulb temperature (Tw), the To and Tw contour lines and contour surfaces are calculated for China. Finally, a comparison between the KSS, AT and WBT methods are provided in which the KSS method is calculated based on air temperature and relative humidity. The results suggest that the KSS method is more appropriate for water phase estimation than are the other methods; the maximum precision for rain and snow is 99% and 94%, respectively. The AT method performs better than the WBT method when the critical air temperature is 2℃.展开更多
With 1 185 pi eces of questionnaire, it is found that in China, people take fresh air, odor, e tc., as well as indoor air temperature, humidity, as the most important indoor a ir parameters. It is also found that ther...With 1 185 pi eces of questionnaire, it is found that in China, people take fresh air, odor, e tc., as well as indoor air temperature, humidity, as the most important indoor a ir parameters. It is also found that there is a significant sensitivity differen ce in indoor environment between southerners and northerners in China. People fr om different regions have different demands for their working and living environ ment. Therefore, as a good design of air conditioning system, it is strongly rec ommended that the different demands of people from different regions should be t aken into consideration.展开更多
Mt. Qomolangma (Everest), the highest mountain peak in the world, has little been studied extensively from a meteorological perspective, mostly because of the remoteness of the region and the resultant lack of meteo...Mt. Qomolangma (Everest), the highest mountain peak in the world, has little been studied extensively from a meteorological perspective, mostly because of the remoteness of the region and the resultant lack of meteorological data. An automatic weather station (AWS), the highest in the world, was set up on 27 April 2005 at the Ruopula Pass (6523 m asl) on the northern slope of Mt. Qomolangma by the team of integrated scientific expedition to Mt. Qomolangma. Here its meteorological characteristics were analyzed according to the lo-minute-averaged and 24-hour records of air temperature, relative humidity, air pressure and wind from 1 May to 22 July 2005. It is shown that at 6523 m of Mt. Qomolangma, these meteorological elements display very obvious diurnal variations, and the character of averaged diurnal variation is one-peak-and-one-vale for air temperature, one-vale for relative humidity, two-peak-and-two-vale for air pressure, and one-peak with day-night asymmetry for wind speed. In the 83 days, all the air temperature, relative humidity and air pressure increased with some different fluctuations, while wind speed decreased gradually and wind direction turned from north to south. The variations of relative humidity had great fluctuations and obvious local differences. Then the paper discusses the reason for the characters of diurnal and daily variations. Compared with the corresponding records in May 1960, 5-day-averaged maximums, minimums and diurnal variations of air temperature in May 2005 were apparently lower.展开更多
Analyzing observations of wintertime air temperature in both indoor and outdoor surroundings in Kunming, a city lying in low latitudes, characteristics of temperature and humidity have been studied for the interior of...Analyzing observations of wintertime air temperature in both indoor and outdoor surroundings in Kunming, a city lying in low latitudes, characteristics of temperature and humidity have been studied for the interior of rooms facing north-south under different weather conditions. Significant warming effect has been identified in terms of lowest and daily-mean indoor temperature in the area of Kunming. The heating amplitude ranges from 7.7C to 10.0C and from 4.6C to 5.8C for the interior part of rooms facing the south and from 4.6C to 7.0C and from 1.3C to 4.4C for the interior part of rooms facing the north, respectively for the two elements. The highest air temperature is higher indoor than outdoor for rooms facing the south, but otherwise is usually true for rooms facing the north. Additional findings point out that buildings not only help maintain relatively warm indoor temperature but delay its variation. The diurnal cycle of temperature indoor is smaller and ranges by 40% ~ 48% for south-facing rooms, and by 20% ~ 30% for north-facing rooms, than outdoor, and the highest temperature is about 2 hours late inside the room than outside. It shows how inertly indoor temperature varies. The work also finds that relative humidity is less indoor in southward rooms than in northward ones and difference is the largest on fine days but the smallest when it is overcast. For the diurnal variation, the indoor relative humidity is large at nighttime with small amplitude but small during daytime with large amplitude. The above-presented results can be served as scientific foundation for more research on climate in low-latitude cities and rational design of urban architectures.展开更多
Accurate information on the spatial distribution and temporal change of wetlands is vital to devise effective measures for their protection. This study uses satellite images in 1994 and 2001 to assess the effects of t...Accurate information on the spatial distribution and temporal change of wetlands is vital to devise effective measures for their protection. This study uses satellite images in 1994 and 2001 to assess the effects of topography and proximity to channels on wetland change in Maduo County on the Qinghai-Tibet Plateau, western China. In 1994 wetlands in the study area extended over 6,780.0 km2. They were distributed widely throughout the county, with a higher concentration in the south, and were especially prominent close to streams. The pattern of wetlands demonstrated a bell-shaped distribution curve with elevation, ranging over hill slopes with gradients from 0-19°, the commonest gradient being around 3°. Although the aspects of these hill slopes range over all directions, there is a lower concentration of wetlands facing east and southeast. The extent of wetlands in 2001 decreased to 6,181.1 km2. Marked spatial differentiation in the pattern of wetlands is evident, as their area increased by 1,193.3 km2 at lower elevations but decreased by 1,792.2 km2 at higher ground, resulting in a net decrease of 598.8 km2. In areas with a gradient <2° or >9° the area of wetlands remained approximately consistent from 1994-2001. Newly retained wetlands are situated in relatively flat lowland areas, with no evident preference in terms of aspect. Wetlands on north-, east- and northeast-facing hillslopes with a bearing of 1-86° were more prone to loss of area than other orientations. The altered pattern of wetland distribution from higher to lower elevation on north-facing slopes coincided with the doubling of annual temperature during the same period, suggesting that climate warming could be an important cause.展开更多
Wine is one of the most important Italian export products,and Nebbiolo is one of the most respected Italian grapes. In the summer of 2007,a measurement campaign was carried out in a Nebbiolo vineyard located in Vezza ...Wine is one of the most important Italian export products,and Nebbiolo is one of the most respected Italian grapes. In the summer of 2007,a measurement campaign was carried out in a Nebbiolo vineyard located in Vezza d’Alba,near Cuneo,Italy. Using a gauge of trade gases and some other instruments,we recorded the stomatal conductance and also some physiological parameters useful for estimating the dependence of stomatal conductance on environmental variables. The goal of this experiment was improving the parameterization of grapevine evapotranspiration through the assessment of the stomatal conductance and,in particular,of the functional dependence of the stomatal conductance on the following variables:the photosynthetically active radiation,the atmospheric temperature,the atmospheric moisture deficit,and the carbon dioxide concentration. The observations allowed us to check and,in some cases,to adapt the existing general parameterizations found in literature. The results showed some significant differences with the existing parameterizations concerning the atmospheric temperature,the atmospheric moisture deficit,and the carbon dioxide concentration. The parameterizations obtained in this experiment,although referring to a specific plant and site(namely the Nebbiolo at Vezza d’Alba),could allow assessment of the best environmental conditions under which the Nebbiolo grapevine production is the best,and in future could be tested for other grapevines or climates.展开更多
In order to reveal transpiration rates of wetland plants and its relationships to micro-meterological factors in a mountain valley wetland, relative humidity, air temperature, leaf temperature, soil temperature, photo...In order to reveal transpiration rates of wetland plants and its relationships to micro-meterological factors in a mountain valley wetland, relative humidity, air temperature, leaf temperature, soil temperature, photo flux density and transpiration rates were measured once two hours in a Carex meyeriana wetland of the Changbai Mountain valley in dry (July) and wet (September) of 2003, respectively. Results showed that the tendency of "decreasing after increasing" was obvious in wet season. However, a relatively stable trend was observed for the transpiration in dry season.. Generally, the photon flux density of Carex meyeriana was higher in wet season than that in dry season. However, the variabilities of leaf temperature, air temperature and relative humidity were similar in both seasons. Higher transpiration rates of Carex meyeriana leaves were observed in July (varied from 40 to 150 mol·m-2·s-1) compared to those (varied from 7 to 14 mol·m-2·s-1) in September. Transpiration rates were significantly correlated with air temperature (P<0.01), leaf temperature (P<0.01), and wind speed (P<0.05), but correlationship between relative humidity and photo flux density was not significant (P<0.05).展开更多
Latvian children under the age of 7 can spend up to 60 hours per week in daycare centers and therefore it is very important to establish a healthy and comfortable daycare environment that children will find pleasant a...Latvian children under the age of 7 can spend up to 60 hours per week in daycare centers and therefore it is very important to establish a healthy and comfortable daycare environment that children will find pleasant and stimulating to stay in. This study investigates indoor air quality and thermal comfort within six daycare centers (old, renovated and new-built) in moderate climate zone of Latvia. Measurements of carbon dioxide, air temperature and relative humidity were carried out, and data regarding daycare center characteristics and maintenance activities was collected via combination of field visits, record analysis and interviews. It was found that carbon dioxide concentrations exceeded 1000 ppm in 75% of daycare centers studied, with the highest (1356 ppm) measured in a renovated facility with the natural ventilation system. Thus installation of more efficient ventilation system (mechanical) is recommended to provide acceptable indoor air quality, since opening of windows itself cannot provide the optimal conditions indoors. In all facilities the temperature was kept above 20℃ and the average relative humidity was 40±35%, creating comfortable thermal environment for children.展开更多
Our research addresses questions about how micro-climate affects activity abundance of a common and widespread harvestman in an alpine ecosystem. Activity patterns of the Harvestman Mitopus morio(Fabricius, 1779) were...Our research addresses questions about how micro-climate affects activity abundance of a common and widespread harvestman in an alpine ecosystem. Activity patterns of the Harvestman Mitopus morio(Fabricius, 1779) were studied along different alpine gradients in the central Norwegian Scandes. Within a nested design, we surveyed 18 alpine habitats with pitfall traps and microclimatological equipment along oceanic-continental, two elevational, and(fine-scaled) microtopographic gradients. Sites in the oceanic region of the Scandes showed generally higher abundance of M. morio than sites in the continental region. Furthermore, along the elevational gradient, middle-alpine sites showed higher abundances than low-alpine sites. These general patterns are best explained by higher humidity in the oceanic region and in the middlealpine belt. Focusing at a finer scale, i.e. one elevational level within each region, revealed partly opposing activity patterns within relatively short distances. While in the western middle-alpine belt these patterns were best explained by humidityrelated measures but now with higher activity abundance during drier conditions, in the drier eastern middle-alpine belt heat sums rather than humidity were found to be the best explanatoryvariables for the observed patterns. Hence, our results imply a pronounced different reaction of the two populations towards climatic variables that partly even contradict the previously described general pattern. Regardless whether these differences in activity abundance in M. morio are a form of phenotypic plasticity or adaptation, our findings stress the importance of detailed autecological knowledge combined with fine-scaled climatic measurements when aiming at predictions about possible future ecosystem structures and spatiotemporal phenomena. M. morio proves to be an ideal biogeographic model organism for understanding spatio-temporal responses of alpine ecosystems under modified climatic conditions.展开更多
Varroasis is a disease caused by the mite Varroa destructor, which affects honeybees worldwide. It is estimated that it entered Chile in 1992, and it must be controlled through different types of treatments such as th...Varroasis is a disease caused by the mite Varroa destructor, which affects honeybees worldwide. It is estimated that it entered Chile in 1992, and it must be controlled through different types of treatments such as thymol, formic and oxalic acid in different formulations and presentations. This kind of organic products has shown a variable acaricidal capacity, since different factors affect their efficacy such as ambient temperature and humidity, product presentation and location inside the hive, etc.. In Chile, beekeeping takes place in four different climatic zones, in which ambient temperature and humidity as well as the duration of the apicultural season are different. Therefore, the aim of this study was to determine how ambient temperature and humidity influence the efficacy of the organic treatments used in the beekeeping season. Different apiaries were installed in those climatic zones in three seasons between the years 2009 and 2012. All beehives received the same management in each apiary and it was evaluated the same organic treatments in different formulations and presentations. All the beehives were positive to Varroa, which was obtained using samples of adult bees and the soapy water test before and after each treatment. A thermo-hygrometer was installed in each apiary in order to monitor the ambient temperature (T°) and humidity (H°) conditions, which were registered daily for a period of 30 days since the beginning. It was obtained that the treatments' efficacy increases as the minimum T° and average T° rose, whereas on the contrary, the efficacy decreases when maximum H° was higher.展开更多
This study is to understand the impact of operating condition, especially initial operation temperature (Tini) which is set in high temperature range, on the temperature profile of the interface between PEM (polyme...This study is to understand the impact of operating condition, especially initial operation temperature (Tini) which is set in high temperature range, on the temperature profile of the interface between PEM (polymer electrolyte membrane) and catalyst layer at the cathode (i.e., the reaction surface) in a single PEFC (polymer electrolyte fuel cell). A 1D multi-plate heat transfer model based on the temperature data of separator measured using thermograph in a power generation experiment was developed to evaluate the reaction surface temperature (Treact). This study investigated the effects of flow rate, relative humidity and type of supply gas as well as Tini on the temperature distribution on reaction surface. The results obtained in 02 supply case show that, the temperature rise at the segments near the outlet of cell decreases with increasing Tini irrespective of relative humidity of supply gas (RH), while it is not seen in air supply case. Regarding the segments except near the outlet in 02 supply case, Treact - Tini increases with increasing Tini for 40% RH. The temperature distribution on reaction surface in 02 supply case is wider with increasing Tini as well as decreasing RH, though that in air supply case is relatively even.展开更多
Climate is an important factor that affects the livability of a region.The climate suitability of a region’s environment for human settlement profoundly affects the regional socio-economic development and the populat...Climate is an important factor that affects the livability of a region.The climate suitability of a region’s environment for human settlement profoundly affects the regional socio-economic development and the population distribution.Tibet is an area that is sensitive to climate change.Given the impact of global climate change,the climate suitability of Tibet has undergone significant changes.In this study,the temperature humidity index(THI)values for Tibet were calculated,and the relationships between the population distribution and the THI were analyzed quantitatively.In this way,the zoning standards for climate suitability in Tibet were determined such that the climate suitability could be evaluated.The results show that the average annual temperature in the southeast of Tibet,where the population was densely distributed,was relatively high.The mean annual relative humidity showed a trend of gradually decreasing from south to north.Regions with a suitable climate,including the high suitability areas(HSAs),the moderately suitable areas(MSAs)and the low suitability areas(LSAs),accounted for only 7.90%of the total area but accommodated over 40%of the total population.The critically suitable areas(CSAs)accounted for 37.81%of the land area and 48.24%of the total population.Non-suitable areas(NSAs)were widely distributed in Tibet and accounted for 54.29%of the total area and 11.33%of the total population.The results of this study may provide a reference for guiding the reasonable distribution of population and promoting the optimization of the spatial planning in Tibet.展开更多
Our analysis of fog and haze observations from the surface weather stations in China in recent 50 years (from 196l to 2011) shows that the number of fog days has experienced two-stage variations, with an increasing ...Our analysis of fog and haze observations from the surface weather stations in China in recent 50 years (from 196l to 2011) shows that the number of fog days has experienced two-stage variations, with an increasing trend before 1980 and a decreasing trend after 1990. Especially, an obvious decreasing trend after 1990 can be clearly seen, which is consistent with the decreas- ing trend of the surface relative humidity. However, the number of haze days has demonstrated an increasing trend. As such, the role of reduction of atmospheric relative humidity in the transition process from fog into haze has been further investigated. It is estimated that the mean relative humidity of haze days is about 69%, lower than previously estimated, which implies that it is more difficult for the haze particles to transform into fog drops. This is possibly one of the major environmental factors leading to the reduction of number of fog days. The threshold of the relative humidity for transition from fog into haze is about 82%, also lower than previously estimated. Thus, the reduction of the surface relative humidity in China mainly due to the in- crease of the surface temperature and the saturation specific humidity may exert an obvious impact on the environmental con- ditions for the formations of fog and haze. In addition, our investigation of the relationship between haze and visibility reveals that with the increase of haze days, the visibility has declined markedly. Since 1961, the mean visibility has dropped from 4-10 to 2-4 kin, about a half of the previous horizontal distance of visibility.展开更多
基金supported by National Natural Science Foundation of China(No.12272184).
文摘The production and utilization of high-energetic explosives often pose a range of safety hazards,with sensitivity being a key factor in evaluating these risks.To investigate how temperature,particle size,and air humidity affect the responsiveness of commonly used high-energetic explosives,a series of BAM(Bundesanstalt für Materialforschung und-prüfung)impact and friction sensitivity tests were carried out to determine the critical impact energy and critical load pressure of four representative high-energetic explosives(RDX,HMX,PETN and CL-20)under different temperatures,particle sizes,and air humidity conditions.The experimental findings facilitated an examination of temperature and particle size affecting the sensitivity of high-energetic explosives,along with an assessment of the influence of air humidity on sensitivity testing.The results clearly indicate that high-energetic explosives display a substantial decline in critical reaction energy when subjected to micrometre-sized particles and an air humidity level of 45%at a temperature of 90℃.Furthermore,it was noted that the critical reaction energy of high-energetic explosives diminishes with an increase in temperature within 25℃−90℃.In the same vein,as the particle sizes of high-energetic explosives increase,so does the critical reaction energy for micrometre-sized particles.High air humidity significantly affects the sensitivity testing of high-energetic explosives,emphasizing the importance of refraining from conducting sensitivity tests in such conditions.
基金Under the auspices of National Natural Science Foundation of China (No. 40830535)Frontier of Northeast Institute of Geography and Agroecology, Chinese Academy of Sciences (No. KZCX3-SW-NA3-01)
文摘The objective of this study is to quantify the values of greenhouse gases(GHGs) exchange in carbon equivalents of marshes and paddy fields in the Sanjiang Plain,Heilongjiang Province,China. We obtained the GHGs exchange values based on comparable price by calculating the carbon sequestration values and the GHGs emission values of marshes and paddy fields respectively in four periods of 1982,1995,2000 and 2005. It is noted that the GHGs emission values are always negative. In this study,the marshes areas decreased from 1438977.0 to 775,132.2ha and the paddy fields areas increased from 417195.8 to 934205.0ha. The values of GHGs exchange of marshes varied from 135877.156×106 to 136882.534×106 yuan(RMB) and those of paddy fields varied from 1006.256×106 to 2767.645×106 yuan. The GHGs exchange values of marshes decreased from 1982 to 2005 on the whole,reversely,those of paddy fields increased,but those in 2005 were lower than those in 2000. In different periods,the GHGs exchange values were always higher in marshes than in paddy fields. The contribution rate of GHGs exchange values per unit area of marshes was also very high in different periods,and the maximum was up to 98.35% in 2005. As far as the whole wetland ecosystem(including marshes and paddy fields) ,assuming a linear change in GHGs exchange values,it represented a cumulative increase of 20926.757×106 yuan from 1982 to 2005. By adding GHGs exchange values increased during those four periods,we obtained a cumulative net increase values of GHGs exchange of wetland ecosystem of 18200.860×106 yuan. The results will be useful for understanding the indirect services provided by marshes and paddy fields.
文摘The regional observed temperature and precipitation changes and their abruptjumps disturbed by large-scale reclamation in the Sanjiang Plain, Northeast China were studied. Meanannual temperature of the region was tending to go up and has increased by 1.2-2.2℃ over the past50 years. A warming jump of mean annual temperature of the region occurred in the 1980s, which hadan increasg amplitude of 0.9℃. Linear tendency rates of annual precipitation were negative in mostof the region. The maximum of annual precipitation decrease was 155.8mm over the past 50 years. Anabrupt decrease of regional annual precipitation happened in the middle of the 1960s, which had adecrease of 102.1mm. Based on the fact of climatic change of the Sanjiang Plain over the past 50years, it is held that the region had larger warming amplitude than that of the surrounding areas inthe recent years, which resulted from the large-scale reclamation of various kinds of wetlands.
基金Major State Basic Research Development Program of China No.G1999043400+1 种基金 National Natural Science Foundation of China No.40375028
文摘Using monthly precipitation and monthly mean temperature, a surface humid index was proposed. According to the index, the distributed characteristics of extreme dryness has been fully analyzed. The results indicated that there is an obvious increasing trend of extreme dryness in the central part of northern China and northeastern China in the last 10 years, which shows a high frequency period of extreme dryness; while a low frequency period in the regions during the last 100 years. Compared with variation trend of the temperature in these regions, the region of high frequent extreme dryness is consistent with the warming trend in the same region.
文摘This study aimed to conduct statistical analysis of temperature,relative humidity,wind direction,wind velocity,deep ground temperature and other related data from National Meteorological Observing Station of Hejian City in 2012.According to the results,observation data varied due to different instruments and equipments,surrounding environments and underlying surface properties.The difference value of monthly average temperature between new site and old site ranged from-0.5 to 0 ℃; the difference value of monthly average maximum temperature ranged from-0.4 to 0.2 ℃; the difference value of monthly average minimum temperature ranged from-0.8 to 0 ℃; the difference value of monthly extreme maximum temperature ranged from-1.1 to 0.6 ℃; the difference value of monthly extreme minimum temperature ranged from-1.2 to 0.3 ℃.Annual average temperature,annual average maximum temperature and annual average minimum temperature in new site were lower than those in old site; annual extreme maximum temperature in new site was higher than that in old site; annual extreme minimum temperature in new site was lower than that in old site.The difference value of monthly average relative humidity between new site and old site ranged from 2% to 6%; the difference value of monthly minimum relative humidity ranged from-4% to 5%.Annual minimum relative humidity in new site was consistent with that in old site.The difference value of 2 min average wind velocity between new site and old site ranged from-0.1 to 0.4 m/s; the difference value of monthly maximum wind velocity ranged from-1.2 to 2.2 m/s; the difference value of monthly extreme wind velocity ranged from-2.0 to 2.8 m/s.Annual maximum wind velocity in new site was basically consistent with that in old site; annual extreme wind velocity in new site was significantly higher than that in old site; annual wind direction frequency in new site was lower than that in old site; annual most frequent wind direction in new site was S and that in old site was SSW.The difference value of average temperature at the depth of 40 cm ranged from-1.1 to 2.5 ℃; the difference value of average temperature at the depth of 80 cm ranged from-2.4 to 2.1 ℃; the difference value of average temperature at the depth of 160 cm ranged from-2.5 to 2.7 ℃; the difference value of average temperature at the depth of 320 cm ranged from-1.6 to 1.1 ℃.Annual average temperatures at the depths of 40 and 160 cm in new site were higher than those in old site,while annual average temperatures at the depths of 80 and 320 cm in new site were lower than those in old site.This paper provided certain correction stand for the use of observation data from new and old sites.
基金Supported by the Natural Science Foundation of Jiangsu Province (BK97124) the National Natural Science Foundation (No. 20376032)+1 种基金 the Outstanding Youth Fund of National Natural Science Foundation (No. 29925616)Key Fund of National Natural Science Fo
文摘Humidification is an important step in humid air turbine system. The calculation on humidification is carried out at 423.15—573.15K, 5—15MPa. The results suggest that to produce high-enthalpy moist air, high water temperature and large water flow are needed. The water temperature is the most sensitive parameter to the humidification tower. And it is better for the humidification tower to work at temperature higher than 523 K when the system pressure is higher than 5 MPa. The comparison between the model used in this paper and ideal model shows that the ideal model can be used in simulation to simply the calculation when the temperature is lower than 473 K and pressure is lower than 5 MPa.
基金supported by National asic Research Program of China (Grant Nos. 013CBA01806)National Natural Sciences oundation of China (Grant Nos. 91025011, 1222001)
文摘The results from three methods aimed at improving precipitation type (e.g., rain, sleet, and snow) estimation are presented and compared in this paper. The methods include the threshold air temperature (AT), threshold wet bulb temperature (WBT) and Koistinen and Saltikoff (KSS) methods. Dot graphs are plotted to acquire the threshold air temperature or the threshold wet bulb temperature using daily averaged air temperature, wet bulb temperature and precipitation data at 643 stations from 1961 to 1979 (precipitation types are not labeled in the database from 1980 to present) in China. The results indicate that the threshold AT or WBT methods are not able to differentiate rain, sleet and snow in the most regions in China; sleet is difficult to differentiate from other precipitation types based on the two threshold methods. Therefore, one threshold AT and WBT method was used in this study to differentiate rain and snow. Based on Gaussian- Kriging interpolation of threshold air temperature (To) and wet bulb temperature (Tw), the To and Tw contour lines and contour surfaces are calculated for China. Finally, a comparison between the KSS, AT and WBT methods are provided in which the KSS method is calculated based on air temperature and relative humidity. The results suggest that the KSS method is more appropriate for water phase estimation than are the other methods; the maximum precision for rain and snow is 99% and 94%, respectively. The AT method performs better than the WBT method when the critical air temperature is 2℃.
文摘With 1 185 pi eces of questionnaire, it is found that in China, people take fresh air, odor, e tc., as well as indoor air temperature, humidity, as the most important indoor a ir parameters. It is also found that there is a significant sensitivity differen ce in indoor environment between southerners and northerners in China. People fr om different regions have different demands for their working and living environ ment. Therefore, as a good design of air conditioning system, it is strongly rec ommended that the different demands of people from different regions should be t aken into consideration.
基金partially funded by the National Nature Science Foundation of China(Grant No.40501015)the Chinese Academy of Science(Grant No.KZCX3-SW-354 and KZCX3-SW-344).
文摘Mt. Qomolangma (Everest), the highest mountain peak in the world, has little been studied extensively from a meteorological perspective, mostly because of the remoteness of the region and the resultant lack of meteorological data. An automatic weather station (AWS), the highest in the world, was set up on 27 April 2005 at the Ruopula Pass (6523 m asl) on the northern slope of Mt. Qomolangma by the team of integrated scientific expedition to Mt. Qomolangma. Here its meteorological characteristics were analyzed according to the lo-minute-averaged and 24-hour records of air temperature, relative humidity, air pressure and wind from 1 May to 22 July 2005. It is shown that at 6523 m of Mt. Qomolangma, these meteorological elements display very obvious diurnal variations, and the character of averaged diurnal variation is one-peak-and-one-vale for air temperature, one-vale for relative humidity, two-peak-and-two-vale for air pressure, and one-peak with day-night asymmetry for wind speed. In the 83 days, all the air temperature, relative humidity and air pressure increased with some different fluctuations, while wind speed decreased gradually and wind direction turned from north to south. The variations of relative humidity had great fluctuations and obvious local differences. Then the paper discusses the reason for the characters of diurnal and daily variations. Compared with the corresponding records in May 1960, 5-day-averaged maximums, minimums and diurnal variations of air temperature in May 2005 were apparently lower.
文摘Analyzing observations of wintertime air temperature in both indoor and outdoor surroundings in Kunming, a city lying in low latitudes, characteristics of temperature and humidity have been studied for the interior of rooms facing north-south under different weather conditions. Significant warming effect has been identified in terms of lowest and daily-mean indoor temperature in the area of Kunming. The heating amplitude ranges from 7.7C to 10.0C and from 4.6C to 5.8C for the interior part of rooms facing the south and from 4.6C to 7.0C and from 1.3C to 4.4C for the interior part of rooms facing the north, respectively for the two elements. The highest air temperature is higher indoor than outdoor for rooms facing the south, but otherwise is usually true for rooms facing the north. Additional findings point out that buildings not only help maintain relatively warm indoor temperature but delay its variation. The diurnal cycle of temperature indoor is smaller and ranges by 40% ~ 48% for south-facing rooms, and by 20% ~ 30% for north-facing rooms, than outdoor, and the highest temperature is about 2 hours late inside the room than outside. It shows how inertly indoor temperature varies. The work also finds that relative humidity is less indoor in southward rooms than in northward ones and difference is the largest on fine days but the smallest when it is overcast. For the diurnal variation, the indoor relative humidity is large at nighttime with small amplitude but small during daytime with large amplitude. The above-presented results can be served as scientific foundation for more research on climate in low-latitude cities and rational design of urban architectures.
基金supported by the International Science & Technology Cooperation Program of China (Grant No. 2011DFG93160,2011DFA20820)the National Natural Sciences Foundation of China (Grant No.41161084)the Scientific Research Collaboration and Training of Top Scientists project (Document No. 2009-1599),Department of International Exchange & Cooperation of the Chinese Ministry of Education
文摘Accurate information on the spatial distribution and temporal change of wetlands is vital to devise effective measures for their protection. This study uses satellite images in 1994 and 2001 to assess the effects of topography and proximity to channels on wetland change in Maduo County on the Qinghai-Tibet Plateau, western China. In 1994 wetlands in the study area extended over 6,780.0 km2. They were distributed widely throughout the county, with a higher concentration in the south, and were especially prominent close to streams. The pattern of wetlands demonstrated a bell-shaped distribution curve with elevation, ranging over hill slopes with gradients from 0-19°, the commonest gradient being around 3°. Although the aspects of these hill slopes range over all directions, there is a lower concentration of wetlands facing east and southeast. The extent of wetlands in 2001 decreased to 6,181.1 km2. Marked spatial differentiation in the pattern of wetlands is evident, as their area increased by 1,193.3 km2 at lower elevations but decreased by 1,792.2 km2 at higher ground, resulting in a net decrease of 598.8 km2. In areas with a gradient <2° or >9° the area of wetlands remained approximately consistent from 1994-2001. Newly retained wetlands are situated in relatively flat lowland areas, with no evident preference in terms of aspect. Wetlands on north-, east- and northeast-facing hillslopes with a bearing of 1-86° were more prone to loss of area than other orientations. The altered pattern of wetland distribution from higher to lower elevation on north-facing slopes coincided with the doubling of annual temperature during the same period, suggesting that climate warming could be an important cause.
文摘Wine is one of the most important Italian export products,and Nebbiolo is one of the most respected Italian grapes. In the summer of 2007,a measurement campaign was carried out in a Nebbiolo vineyard located in Vezza d’Alba,near Cuneo,Italy. Using a gauge of trade gases and some other instruments,we recorded the stomatal conductance and also some physiological parameters useful for estimating the dependence of stomatal conductance on environmental variables. The goal of this experiment was improving the parameterization of grapevine evapotranspiration through the assessment of the stomatal conductance and,in particular,of the functional dependence of the stomatal conductance on the following variables:the photosynthetically active radiation,the atmospheric temperature,the atmospheric moisture deficit,and the carbon dioxide concentration. The observations allowed us to check and,in some cases,to adapt the existing general parameterizations found in literature. The results showed some significant differences with the existing parameterizations concerning the atmospheric temperature,the atmospheric moisture deficit,and the carbon dioxide concentration. The parameterizations obtained in this experiment,although referring to a specific plant and site(namely the Nebbiolo at Vezza d’Alba),could allow assessment of the best environmental conditions under which the Nebbiolo grapevine production is the best,and in future could be tested for other grapevines or climates.
基金supported by the National Basic Research Program of China (No.2006CB403301)the National Natural Science Foundation Project (4)the Emphasis Project Fund of National Eleventh Five-Year Scientific and Technical Support Plans (No.2006BAB04A08)
文摘In order to reveal transpiration rates of wetland plants and its relationships to micro-meterological factors in a mountain valley wetland, relative humidity, air temperature, leaf temperature, soil temperature, photo flux density and transpiration rates were measured once two hours in a Carex meyeriana wetland of the Changbai Mountain valley in dry (July) and wet (September) of 2003, respectively. Results showed that the tendency of "decreasing after increasing" was obvious in wet season. However, a relatively stable trend was observed for the transpiration in dry season.. Generally, the photon flux density of Carex meyeriana was higher in wet season than that in dry season. However, the variabilities of leaf temperature, air temperature and relative humidity were similar in both seasons. Higher transpiration rates of Carex meyeriana leaves were observed in July (varied from 40 to 150 mol·m-2·s-1) compared to those (varied from 7 to 14 mol·m-2·s-1) in September. Transpiration rates were significantly correlated with air temperature (P<0.01), leaf temperature (P<0.01), and wind speed (P<0.05), but correlationship between relative humidity and photo flux density was not significant (P<0.05).
文摘Latvian children under the age of 7 can spend up to 60 hours per week in daycare centers and therefore it is very important to establish a healthy and comfortable daycare environment that children will find pleasant and stimulating to stay in. This study investigates indoor air quality and thermal comfort within six daycare centers (old, renovated and new-built) in moderate climate zone of Latvia. Measurements of carbon dioxide, air temperature and relative humidity were carried out, and data regarding daycare center characteristics and maintenance activities was collected via combination of field visits, record analysis and interviews. It was found that carbon dioxide concentrations exceeded 1000 ppm in 75% of daycare centers studied, with the highest (1356 ppm) measured in a renovated facility with the natural ventilation system. Thus installation of more efficient ventilation system (mechanical) is recommended to provide acceptable indoor air quality, since opening of windows itself cannot provide the optimal conditions indoors. In all facilities the temperature was kept above 20℃ and the average relative humidity was 40±35%, creating comfortable thermal environment for children.
基金partly sponsored by Color Line Aksjeselskap, Oslo
文摘Our research addresses questions about how micro-climate affects activity abundance of a common and widespread harvestman in an alpine ecosystem. Activity patterns of the Harvestman Mitopus morio(Fabricius, 1779) were studied along different alpine gradients in the central Norwegian Scandes. Within a nested design, we surveyed 18 alpine habitats with pitfall traps and microclimatological equipment along oceanic-continental, two elevational, and(fine-scaled) microtopographic gradients. Sites in the oceanic region of the Scandes showed generally higher abundance of M. morio than sites in the continental region. Furthermore, along the elevational gradient, middle-alpine sites showed higher abundances than low-alpine sites. These general patterns are best explained by higher humidity in the oceanic region and in the middlealpine belt. Focusing at a finer scale, i.e. one elevational level within each region, revealed partly opposing activity patterns within relatively short distances. While in the western middle-alpine belt these patterns were best explained by humidityrelated measures but now with higher activity abundance during drier conditions, in the drier eastern middle-alpine belt heat sums rather than humidity were found to be the best explanatoryvariables for the observed patterns. Hence, our results imply a pronounced different reaction of the two populations towards climatic variables that partly even contradict the previously described general pattern. Regardless whether these differences in activity abundance in M. morio are a form of phenotypic plasticity or adaptation, our findings stress the importance of detailed autecological knowledge combined with fine-scaled climatic measurements when aiming at predictions about possible future ecosystem structures and spatiotemporal phenomena. M. morio proves to be an ideal biogeographic model organism for understanding spatio-temporal responses of alpine ecosystems under modified climatic conditions.
文摘Varroasis is a disease caused by the mite Varroa destructor, which affects honeybees worldwide. It is estimated that it entered Chile in 1992, and it must be controlled through different types of treatments such as thymol, formic and oxalic acid in different formulations and presentations. This kind of organic products has shown a variable acaricidal capacity, since different factors affect their efficacy such as ambient temperature and humidity, product presentation and location inside the hive, etc.. In Chile, beekeeping takes place in four different climatic zones, in which ambient temperature and humidity as well as the duration of the apicultural season are different. Therefore, the aim of this study was to determine how ambient temperature and humidity influence the efficacy of the organic treatments used in the beekeeping season. Different apiaries were installed in those climatic zones in three seasons between the years 2009 and 2012. All beehives received the same management in each apiary and it was evaluated the same organic treatments in different formulations and presentations. All the beehives were positive to Varroa, which was obtained using samples of adult bees and the soapy water test before and after each treatment. A thermo-hygrometer was installed in each apiary in order to monitor the ambient temperature (T°) and humidity (H°) conditions, which were registered daily for a period of 30 days since the beginning. It was obtained that the treatments' efficacy increases as the minimum T° and average T° rose, whereas on the contrary, the efficacy decreases when maximum H° was higher.
文摘This study is to understand the impact of operating condition, especially initial operation temperature (Tini) which is set in high temperature range, on the temperature profile of the interface between PEM (polymer electrolyte membrane) and catalyst layer at the cathode (i.e., the reaction surface) in a single PEFC (polymer electrolyte fuel cell). A 1D multi-plate heat transfer model based on the temperature data of separator measured using thermograph in a power generation experiment was developed to evaluate the reaction surface temperature (Treact). This study investigated the effects of flow rate, relative humidity and type of supply gas as well as Tini on the temperature distribution on reaction surface. The results obtained in 02 supply case show that, the temperature rise at the segments near the outlet of cell decreases with increasing Tini irrespective of relative humidity of supply gas (RH), while it is not seen in air supply case. Regarding the segments except near the outlet in 02 supply case, Treact - Tini increases with increasing Tini for 40% RH. The temperature distribution on reaction surface in 02 supply case is wider with increasing Tini as well as decreasing RH, though that in air supply case is relatively even.
基金The Second Tibetan Plateau Scientific Expedition and Research Program(2019QZKK1006)The Strategic Priority Research Program of Chinese Academy of Sciences(XDA20010201,XDA20010203)+1 种基金The National Natural Science Foundation of China(41901086,41901260)The Beijing Natural Science Foundation(5204033)。
文摘Climate is an important factor that affects the livability of a region.The climate suitability of a region’s environment for human settlement profoundly affects the regional socio-economic development and the population distribution.Tibet is an area that is sensitive to climate change.Given the impact of global climate change,the climate suitability of Tibet has undergone significant changes.In this study,the temperature humidity index(THI)values for Tibet were calculated,and the relationships between the population distribution and the THI were analyzed quantitatively.In this way,the zoning standards for climate suitability in Tibet were determined such that the climate suitability could be evaluated.The results show that the average annual temperature in the southeast of Tibet,where the population was densely distributed,was relatively high.The mean annual relative humidity showed a trend of gradually decreasing from south to north.Regions with a suitable climate,including the high suitability areas(HSAs),the moderately suitable areas(MSAs)and the low suitability areas(LSAs),accounted for only 7.90%of the total area but accommodated over 40%of the total population.The critically suitable areas(CSAs)accounted for 37.81%of the land area and 48.24%of the total population.Non-suitable areas(NSAs)were widely distributed in Tibet and accounted for 54.29%of the total area and 11.33%of the total population.The results of this study may provide a reference for guiding the reasonable distribution of population and promoting the optimization of the spatial planning in Tibet.
基金supported by National Key Basic Research Program of China(Grant Nos.2012CB417205 and 2013CB430202)the National Natural Science Foundation of China(Grant No.41130960)National Science and Technology Support Program of China(Grant No.2009BAC51B02)
文摘Our analysis of fog and haze observations from the surface weather stations in China in recent 50 years (from 196l to 2011) shows that the number of fog days has experienced two-stage variations, with an increasing trend before 1980 and a decreasing trend after 1990. Especially, an obvious decreasing trend after 1990 can be clearly seen, which is consistent with the decreas- ing trend of the surface relative humidity. However, the number of haze days has demonstrated an increasing trend. As such, the role of reduction of atmospheric relative humidity in the transition process from fog into haze has been further investigated. It is estimated that the mean relative humidity of haze days is about 69%, lower than previously estimated, which implies that it is more difficult for the haze particles to transform into fog drops. This is possibly one of the major environmental factors leading to the reduction of number of fog days. The threshold of the relative humidity for transition from fog into haze is about 82%, also lower than previously estimated. Thus, the reduction of the surface relative humidity in China mainly due to the in- crease of the surface temperature and the saturation specific humidity may exert an obvious impact on the environmental con- ditions for the formations of fog and haze. In addition, our investigation of the relationship between haze and visibility reveals that with the increase of haze days, the visibility has declined markedly. Since 1961, the mean visibility has dropped from 4-10 to 2-4 kin, about a half of the previous horizontal distance of visibility.