[ Objective] The study was to compare the structural and moisture characteristics of leaf from the plantlets of three types of omamental lily( Lilium brownii). [ Method ] The paraffin sections of leaves of tested li...[ Objective] The study was to compare the structural and moisture characteristics of leaf from the plantlets of three types of omamental lily( Lilium brownii). [ Method ] The paraffin sections of leaves of tested lily varieties were prepared and then observed under microscope, and the stomatal characteristics and moisture characteristics of tested lily varieties were measured. I Resaltl All the three ornamental lily varieties show isobilateral leaf, single layer of epicuticula and lower epidermis, and no obvious differentiation of palisade tissue and spongy tissue; their stomata distribute in lower epidermis, and the guard cells are dumbbell-shaped; all of these matedais present high moisture. For the leaf sick- ness, midrib sickness and mesophyll tissue sickness, the order was determined to be oriental lily 〉 Lilium/ongiflorum 〉 Asian lily; of the three types of ornamental lily, Ulium Iongiflorum has the largest stomatai aperture and Asian lily has the smallest; focusing the water potential and moisture, the turn was Asian lily 〉 oriental lily 〉 Lilium Iong'fflorum. [ Condusion] The study may facilitate the artificial regulation of the growth conditions of the plantlets of ornamental lily.展开更多
Robinia pseudoacacia stands act as a typical ecological protection forest in hilly semi-arid area of China. Two fields of surface runoff were separately set up in R. pseudoacacia stand and its clearcut area in the wes...Robinia pseudoacacia stands act as a typical ecological protection forest in hilly semi-arid area of China. Two fields of surface runoff were separately set up in R. pseudoacacia stand and its clearcut area in the western Liaoning Province (1850-12225 E, 4024-4234 N) for measuring the characteristics of runoff and sediment as well as soil moisture dynamics. Contractive analysis of the two land types showed that there existed a significant difference in volumes of runoff and sediment between the sites of R. pseudoacacia stand and its clearcut area. The runoff volume and sediment volume in clearcut area were much bigger than those in R. pseudoacacia stand, with an increase amount of 40%-177% for runoff and 180%-400% for sediment. Hydrograph of surface runoff of typical rainfall showed that the peak value of runoff in R. pseudoacacia stand was decreased by 1.0-2.5?0-3m3s-1 compared with that in its clearcut area, and the occurring time of peak value of runoff in R. pseudoacacia stand was 10-20 min later than that in its clearcut area. Harmonic analysis of soil moisture dynamics indicated that the soil moisture in R. pseudoacacia stand was 2.3 % higher than that in clearcut area, and the soil moisture both in R. pseudoacacia stand and its clearcut area could be divided into dry season and humid season and varied periodically with annual rainfall precipitation. It was concluded that R. pseudoacacia stand plays a very important role in storing water, increasing soil moisture, and reducing surface runoff and soil erosion.展开更多
Ecological efficiency changes of soil moisture were researched in karst areas with different land type uses, including farmland, abandoned farmland (1 y) and shrub land (1 y), sparse wood land (15 y), secondary ...Ecological efficiency changes of soil moisture were researched in karst areas with different land type uses, including farmland, abandoned farmland (1 y) and shrub land (1 y), sparse wood land (15 y), secondary forest (25 y) and the re- sults showed that physical property of soil was not a simple "improvement" process during land type evolution. Specifically, from farmland to secondary forest, the con- tent of topsoils changed from being washed away to accumulation and soil bulk density changed from increasing to decreasing. For example, soil bulk densities of abandoned farmland and shrub land increased by 6.6% and 11.57% compared with farmland, and of sparse wood land and forest land decreased by 5.0% and 10.0%. The change trend of soil bulk density was just in contrary to total porosity. Available water capacity was the lowest of shrub land, but increased in rest land types. The increase tended to be volatile in 5.1%-12.5% of different land types and water-sta- ble aggregate content (〉0.25 mm) reached the highest of sparse wood land. The destruction rate, however, was declining in the process of land type evolution and the increase was in the range of 34.0%-64.7% compared with farmland. The de- struction rate of aggregate was of negative correlation with organic matter. Water- holding capacity was the best of forest land and abandoned farmland and the poor- est of shrub land, close to sparse wood land. Water-supplying capacity from high to low was as follows: farmland〉sparse wood land〉secondary forest〉shrub land〉a- bandoned farmland. It is obvious that water-holding capacity and water-supplying capacity are not consistent, but both are closely related to the content of soil clays, porosity, and aggregate stability.展开更多
We investigated the combined effects of soil moisture and light intensity on the growth, development and ecophysiological characteristics of one-year old Amorpha fruticosa seedlings. Soil moisture and light intensity ...We investigated the combined effects of soil moisture and light intensity on the growth, development and ecophysiological characteristics of one-year old Amorpha fruticosa seedlings. Soil moisture and light intensity influenced the ecophysiological characteristics of Amorpha fruticosa seedlings. Soil moisture resulted in the decreases of growth rate, individual size, net photosynthetic rate, transpiration rate, leaf water loss rate (WLR), and biomass accumulation of plant parts, and led to increased leaf water saturation deficit (WSD). Under water stress, more photosynthetic products were allocated to root growth. With decreasing light intensity, net photosynthetic rate, transpiration rate, chla/b, water saturation deficit, water use efficiency, water loss rate and biomass accumulation declined, while Chla, Chlb, Chla+b and carotenoids (Car) increased and more photosynthetic products were allocated to stem and leaf growth. Maximum growth vigor, net photosynthetic rate and total biomass accumulation in Amorpha fruticosa seedlings was recorded at 75 80% soil water-holding capacity and 100% light density in greenhouse environments.展开更多
The climatological characteristics of the moisture budget over the joining area of Asia and the IndianPacific Ocean (AIPO) and its adjacent regions as well as their anomalies have been estimated in this study. The m...The climatological characteristics of the moisture budget over the joining area of Asia and the IndianPacific Ocean (AIPO) and its adjacent regions as well as their anomalies have been estimated in this study. The main results are as follows. In the winter, the northeasterly moisture transport covers the extensive areas at the lower latitudes of the AIPO. The westerly and northerly moisture transport is the major source and the South Indian Ocean (SIO) is the moisture sink. In the summer, influenced by the southwesterly monsoonal wind, the crossequatorial southwesterly moisture transport across Somali originating from the SIO is transported through the Arabian Sea (AS), the Bay of Bengal (BOB), and the South China Sea (SCS) to eastern China. The AIPO is controlled by the southwesterly moisture transport. The net moisture influx over the AIPO has obvious interannual and interdecadal variations. From the mid- or late 1970s, the influxes over the SIO, the AS, the northern part of the western North Pacific (NWNP), and North China (NC) as well as South China (SC) begin to decrease abruptly, while those over Northeast China (NEC) and the Yangtze River-Huaihe River basins (YHRB) have increased remarkably. As a whole, the net moisture influxes over the BOB and the southern part of the western North Pacific (SWNP) in the recent 50 years take on a linear increasing trend. However, the transition timing for these two regions is different with the former being at the mid- or late 1980s and the latter occurring earlier, approximately at the early stage of the 1970s. The anomalous moisture source associated with the precipitation anomalies is different from the normal conditions of the summer precipitation. For the drought or flood years or the years of E1 Nifio and its following years, the anomalous moisture transport originating from the western North Pacific (WNP) is the vital source of the anomalous precipitation over eastern China, which is greatly related with the variation of the subtropical Pacific high.展开更多
An experiment about rice milling was made to study on the relationship between the different moisture content of brown rice and the energy consumption, the broken rice rate, the crack rate and the head rice yield. It ...An experiment about rice milling was made to study on the relationship between the different moisture content of brown rice and the energy consumption, the broken rice rate, the crack rate and the head rice yield. It could be concluded that the head rice yield increased at first falls and then along with the raise of moisture content and it could reach the maximum 70.78% when moisture content was 15.5%; the energy consumption of rice milling decreased along with the increase of moisture contents; the broken rice rate fell at first and then increased along with the raise of moisture contents and it could reach the minimum 4.28% when the moisture content was 15.5%.展开更多
The effects of moisture content on the combustion characteristics and pore structure change of coal slime are studied in this paper.The effect of moisture content on the bed temperature change,combustion efficiency,an...The effects of moisture content on the combustion characteristics and pore structure change of coal slime are studied in this paper.The effect of moisture content on the bed temperature change,combustion efficiency,and NO_(x)and SO_(2)emission were obtained in a bench⁃scale fluidized bed reactor,revealing that the lowest bed temperature decreases with the increase in moisture content,but the effect on the highest bed temperature is not the same.Moreover,with the increase in moisture content,the observed degree of blackening of the flue gas increased,and more CO was produced,which in turn leads to a lower combustion efficiency of the coal slime.However,the presence of moisture plays a positive role in the reduction of NO_(x)and SO_(2).With the increase in moisture content,the amount of NO_(x)and SO_(2)produced tends to decrease.The effect of water on the combustion process of slime is mostly the impact of the severe vaporization process in the early stage to form a large water vapor channel,which is beneficial to the evaporation and loss of water,conducive to the reaction of water and coal combustion products,such as the formation of CO,reduction of NO_(x),SO_(2),etc.The large holes formed by the impact of water vapor decreased with the decrease of moisture content,and the nanoscale pores are mostly caused by the combustion process of volatilization and coke formation after the end of vaporization,and increase with the decrease of moisture content.展开更多
Apparent moisture sink and water vapor transport flux are calculated by using NCAR/NCEP reanalyzed daily data for water vapor and wind fields at various levels from 1980 to 1989.With the aid of EOF analysis method,tem...Apparent moisture sink and water vapor transport flux are calculated by using NCAR/NCEP reanalyzed daily data for water vapor and wind fields at various levels from 1980 to 1989.With the aid of EOF analysis method,temporal and spatial characteristics of moisture budgets over Asian and Australian monsoon regions are studied.The results show that there is apparent seasonal transition of moistrue sink and water vapor transport between Asian monsoon region and Australian monsoon region.In winter,the Asian monsoon region is a moisture source,in which three cross-equatorial water vapor transport channels in the 'continent bridge',at 80°E and 40°E~50° transport water vapor to the Australian monsoon region and southern Indian Ocean which are moistrue sinks.In summer,Australian Monsoon region anmd southern Indian Ocean are moistrue sources and by the three cross-equatorial transport channels water vapor is transport to the Asian monsoon region which is a moisture sink.In spring and autumn,ITCZ is the main moisture sink and there is no apparent water vapor transport between Asian monsoon region and Australian monsoon region.展开更多
This study investigates the impact of soil moisture availability on dispersion-related characteristics: surface friction velocity (u* ), characteristic scales of temperature and humidity (T * and q * ), the planetary ...This study investigates the impact of soil moisture availability on dispersion-related characteristics: surface friction velocity (u* ), characteristic scales of temperature and humidity (T * and q * ), the planetary boundary layer height (h) and atmospheric stability classified by Monin-Obukhov length (L), Kazanski-Monin parameter (μ) and convective velocity scale (w* ) during daytime convective condition using a one-dimensional primitive equation with a refined soil model.展开更多
Soil moisture (SM) is one of the important parameters in the process of land-atmosphere interactions. The spatial-temporal distribution of SM plays a significant role in weather and climate research. In this study, ba...Soil moisture (SM) is one of the important parameters in the process of land-atmosphere interactions. The spatial-temporal distribution of SM plays a significant role in weather and climate research. In this study, based on the monthly SM datasets from GLDAS (Global Land Surface Data Assimilation System), the temporal and spatial changes of shallow SM are discussed, and the applicability of five domestic models from Coupled Model Intercomparison Project 6 (CMIP6) is also evaluated in the Northwest China. The results show that: 1) The shallow SM (0 - 10 cm) in spring in Northwest China was generally low during 1948-2015, and the low value areas were mainly located in the Tarim Basin in Xinjiang and the Gobi and desert areas in western Inner Mongolia. In most parts of Northwest China, SM had an increasing trend in spring, this implies it became wetter in recent 60 years;2) There are larger difference between the five models for simulating SM. Except for BCC-ESM1, all the four models (including BCC-CSM2-MR, FGOALS-f3-L, FGOALS-g3, TaiESM1) can basically simulate the spatial distribution and trend of SM in spring, all the spatial correlation coefficients between the four models and GLDAS data pass the 99% significant level;3) After multi-ensemble mean, the simulation performance can be obviously improved, the spatial correlation can reach about 0.55 in spring, the spatial trend is much closer to the GLDAS.展开更多
Climate change is one of the major global challenges and it can have a significant influence on the behaviour and resilience of geotechnical structures.The changes in moisture content in soil lead to effective stress ...Climate change is one of the major global challenges and it can have a significant influence on the behaviour and resilience of geotechnical structures.The changes in moisture content in soil lead to effective stress changes and can be accompanied by significant volume changes in reactive/expansive soils.The volume change leads to ground movement and can exert additional stresses on structures founded on or within a shallow depth of such soils.Climate change is likely to amplify the ground movement potential and the associated problems are likely to worsen.The effect of atmospheric boundary interaction on soil behaviour has often been correlated to Thornthwaite moisture index(TMI).In this study,the long-term weather data and anticipated future projections for various emission scenarios were used to generate a series of TMI maps for Australia.The changes in TMI were then correlated to the depth of suction change(H s),an important input in ground movement calculation.Under all climate scenarios considered,reductions in TMI and increases in H s values were observed.A hypothetical design scenario of a footing on expansive soil under current and future climate is discussed.It is observed that a design that might be considered adequate under the current climate scenario,may fail under future scenarios and accommodations should be made in the design for such events.展开更多
A soil water retention curve (SWRC) is an essential soil physical property for analyzing transport and retention of water in a soil layer. A SWRC is often described as a single-valued function that relates the soil wa...A soil water retention curve (SWRC) is an essential soil physical property for analyzing transport and retention of water in a soil layer. A SWRC is often described as a single-valued function that relates the soil water potential ψ to volumetric water content θ of the soil. However, an in-situ ψ − θ relation should show soil water hysteresis, though this fact is often neglected in analyses of field soil water regimes while long-term in-situ soil water hysteresis is not well characterized. This study aimed at probing and characterizing in-situ ψ − θ relations. The developments of large hysteresis in the in-situ ψ − θ relations were observed only a few times during the study period of 82 months. Any of the large hysteretic behaviors in the ψ − θ relations began with an unusually strong continual reduction in ψ. The completion of a hysteresis loop required a recorded maximum rainfall. Because the study field had very small chances to meet such strong rainfall events, it took multiple years to restore the fraction of soil water depleted by the unusually strong continual reduction in ψ. While wetting-drying cycles had occurred within a certain domain of ψ, hysteretic behaviors tended to be so small that the in-situ ψ − θ relation can be approximated as a single-valued function of θ(ψ). These observed patterns of the in-situ ψ − θ relations were characterized by kinds of difference in dθ/dψ between a drying process and a wetting process at a given ψ. Thus, more amounts of experimental facts about wetting SWRCs in parallel with drying SWRCs should be needed for correct modelling, analyzing, and predicting soil water regimes in fields. It is also necessary to increase our understandings about the long-term trends of occurrences of extreme weather conditions associated with possible change in climate.展开更多
On the basis of discussing the influencing mode of plant moisture stress on plant physiological process and the division of soil moisture availability range, the water suction values partitioning soil moisture were pu...On the basis of discussing the influencing mode of plant moisture stress on plant physiological process and the division of soil moisture availability range, the water suction values partitioning soil moisture were put forward, and then the corresponding water moistures under water stress were obtained by conversing together with characteristic curve of water moisture.展开更多
For obtaining the drying curve of powder under fluidized drying, a normal fluidized-bed dryer is designed to study the drying kinetics of PVC (polyvinyl chloride) powder in the experiment. A new measure system is de...For obtaining the drying curve of powder under fluidized drying, a normal fluidized-bed dryer is designed to study the drying kinetics of PVC (polyvinyl chloride) powder in the experiment. A new measure system is derived for drying dynamics testing. In the small fluidized-bed dryer, fluidization parameter of PVC powder is tested, and the operating air velocity can be chosen in the range of 0. 41 to 0. 55 m/s. Accordingly, the fluidized number Ua/Umf is from 1.24 to 1.67. A promising drying model is used to describe the drying process, and then the characteristic drying curve of PVC powder derived from a suspension method can be expressed as f = [-0. 622 6 + 1. 254 6exp(2. 561 5Φ -0. 707 2) /[1 + exp(2. 561 5Φ -0. 707 2)] Based on the experiments, the critical moisture content xc and the mass transfer coefficient K are determined to be 0. 02 kg/kg and 6. 0 × 10^-4 kg/( m2 · s), respectively. The experimental results in the small fluidized-bed dryer are similar to those of the real fluidized drying process, so the descried method can also be used in determining drying kinetics of powder materials such as PVC powder.展开更多
[Objective] The aim was to study the effect of salt solution on characteristics of soil infiltration, and to provide references for the further studies on the effect of water quality on soil infiltration characteristi...[Objective] The aim was to study the effect of salt solution on characteristics of soil infiltration, and to provide references for the further studies on the effect of water quality on soil infiltration characteristics and its mechanism. [Method] With the NaCl, CaCl2 solutions as the main test materials, the effect of different water quality and salt solution concentration on soil infiltration was studied under one-dimensional vertical ponded water infiltration at laboratory. [Result] The solution concentration could affect the infiltration performance. The trends of the infiltration rates, cumulative infiltrations and wetting front migration distances were all 50 mg/L 100 mg/L 10 mg/L. At the same concentration, the effect of NaCl solution on soil infiltration characteristics was more significant than CaCl2 solution: in the same time, cumulative infiltration and wetting front migration distance of NaCl solution were greater than CaCl2 solution; compared with NaCl solution, CaCl2 solution took longer time to infiltrate the same amount of water. The dynamic changes of infiltration rate, wetting front and cumulative infiltration were well fitted to the Philip model. [Conclusion] This study only conducted indoor experiment to the infiltration of salt solutions, involving in low concentration and small range. Although it provided some references for the study on the effect of water quality on soil infiltration characteristics and its mechanism, studies in larger areas and with bigger concentrations are demanding.展开更多
In this paper, we study the spatiotemporal characteristics of precipitable water, precipitation, evaporation, and watervapor flux divergence in different seasons over northeast China and the water balance of that area...In this paper, we study the spatiotemporal characteristics of precipitable water, precipitation, evaporation, and watervapor flux divergence in different seasons over northeast China and the water balance of that area. The data used in this paper is provided by the European Center for Medium-Range Weather Forecasts (ECMWF). The results show that the spatial distributions of precipitable water, precipitation, and evaporation feature that the values of elements above in the southeastern area are larger than those in the northwestern area; in summer, much precipitation and evaporation occur in the Changbai Mountain region as a strong moisture convergence region; in spring and autumn, moisture divergence dominates the northeast of China; in winter, the moisture divergence and convergence are weak in this area. From 1979 to 2010, the total precipitation of summer and autumn in northeast China decreased significantly; especially from 1999 to 2010, the summer precipitation always demonstrated negative anomaly. Additionally, other elements in different seasons changed in a truly imperceptible way. In spring, the evaporation exceeded the precipitation in northeast China; in summer, the precipitation was more prominent; in autumn and winter, precipitation played a more dominating role than the evaporation in the northern part of northeast China, while the evaporation exceeded the precipitation in the southern part. The Interim ECMWF Re-Analysis (ERA-Interim) data have properly described the water balance of different seasons in northeast China. Based on ERA-Interim data, the moisture sinks computed through moisture convergence and moisture local variation are quite consistent with those computed through precipitation and evaporation, which proves that ERA- Interim data can be used in the research of water balance in northeast China. On a seasonal scale, the moisture convergence has a greater influence than the local moisture variation on a moisture sink, and the latter is variable slightly, generally as a constant. Likewise, in different seasons, the total precipitation has a much greater influence than the evaporation on the moisture sink.展开更多
The effect of vertical internal baffles on the particle mixing and graindrying characteristics in a batch fluidized bed column is investigated. Experimental work wascarried out in a 3m high rectangular fluidized bed d...The effect of vertical internal baffles on the particle mixing and graindrying characteristics in a batch fluidized bed column is investigated. Experimental work wascarried out in a 3m high rectangular fluidized bed dryer of cross sectional area of 0.15 m x 0.61 mat different operating conditions using paddy, a group D particle, as the fluidizing material. Theresults of the study showed that the fluidized bed dryer system with vertical internal baffles gavebetter particle mixing effect in the bed of particles than that without vertical internal baffles.This is due to the fact that the vertical internal baffle act as gas bubble breakers by breaking upthe large gas bubbles into smaller ones. The smaller bubbles cause a more vigorous mixing in the bedof particles before finally erupting at the bed surface. This improves the contacting efficiencyand enhanced the heat and mass transfer of the fluidized bed system. Thus a higher drying rate wasobtained in the falling rate period because the higher contacting efficiency increases theevaporation rate at the particle surface. However, the drying rate in the diffusion region showslittle improvement because the moisture diffusivity does not depend on the contacting efficiency.The fluidized bed dryer with vertical internal baffles could therefore be used in the initial rapiddrying stage in a two stage drying strategy for paddy. The insertion of vertical internal bafflesinto a fluidized bed system improves the processing of Group D particles in a fluidized bed systemespecially if the system is large in scale.展开更多
Multipurpose tree species (MPTs) were studied in an agroforestry arboretum under subtropical humid climate in Northeast India. Out of 12 MPTs planted under agroforestry systems, Acacia auriculiformis in spacing of 2...Multipurpose tree species (MPTs) were studied in an agroforestry arboretum under subtropical humid climate in Northeast India. Out of 12 MPTs planted under agroforestry systems, Acacia auriculiformis in spacing of 2 m × 2 m (2500 stems·hm^-2) could have the potentiality to meet the timber/fuelwood requirement due to its high wood production of 635 m^3·hm^-2 with mean annual increment (MAI) of 2.54×10^-2 m^3.treel.a^-1 in a short rotation period of 10 years. Thus, A. auriculiformis is a short rotation forest tree species suitable to grow in subtropical humid climate. On the other hand, at 16 years of age, Eucalyptus hybrid and Michelia champaca in spacing of 3 m × 3 m (1111 stems.hm^2) produced appreciably high timber volume of 315 m^3.hm^-2 and 165 m^3.hm^-2 with MAI of 1.77×10^-2 m^3.tree^-1·a^-1 and 0.92×10.2 m^3.tree^-1.a^-1, respectively. At 16 years of age, Gmelina arborea produced a timber volume of 147 m^3.hm^-2 with MAI of 1.47×10^-2 m^3.tree^-1.a^-1 followed by Samania saman (140 m^3.hm^-2), Albizziaprocera (113 m^3·hm^-2) and Tectona grandis (79 m3.hm^-2) with MAI of 1.40, 1.13 and 0.78 × 10^-2 m^3 .tree^-1a^-1, respectively in 4 m × 4 m spacing (625 stems.hm^-2). Gliricidia maculata and Leucaena leucocephala could be used as live fences around the farm boundary to supply their N-rich leaves for mulch as well as manure to crops. In agroforestry arboretum, direct seeded upland rice (Oryza sativa - variety, AR-11), groundnut (Arachis hypogaea - variety, JL-24) and sesamum (Sesamum indicum - variety, B-67) were grown during the initial period upto 8 years of tree establishment. Under other MPTs, there was a reduction in crop productivity as compared to open space. After 8 years of tree establishment, horti-silvi and silvi-pastoral systems were developed and pineapple (Ananas comosus - variety Queen), turmeric (Curcuma longa -variety RCT -1) and cowpea (Vigna sinensis - variety Pusa Barsati) as forage crop were raised. The productivity of pineapple, turmeric and cowpea was comparatively high under Azadirachta indica. The productivity of horticultural and forage crops in association with trees such as G. arborea, A. procera, S. saman, T. grandis and M. champaca of high timber value could be harnessed as viable agroforestry systems. Changes in soil properties were also monitored. Amelioration of soil acidity, increase in soil organic carbon, and enhanced humification of soil humus, high nutrient availability, low soil erodibility and high surface soil (0-15 cm) moisture availability were noted in soils under MPTs.展开更多
The drought characteristics,the relationships between the drought and the meteorological factors,soil moisture content in Jinjiang City were analyzed.The results showed that Jinjiang belonged to the serious area which...The drought characteristics,the relationships between the drought and the meteorological factors,soil moisture content in Jinjiang City were analyzed.The results showed that Jinjiang belonged to the serious area which the drought occurred frequently.The summer drought occurrence frequency which was annual average 1.5 times was the highest.The droughts often occur in the continuous drought form,and the droughts which are above the great drought mainly occur in summer,fall and winter.Since 2000,the probabilities which spring drought and summer drought occurred in Jinjiang have reduced obviously.However,the probabilities which the continuous drought in summer,fall and fall,winter occurred have increased obviously.80% of droughts reached the special drought standard,and the drought disaster's times tended to aggravate and accelerate.The continuous drought days negatively correlated with the precipitation and positively correlated with the sunshine hours.The relativity was the highest.50% of meteorological droughts could cause the soil drought.However,the meteorological drought and the soil drought weren't synchronous.The soil moderate drought often happens in the meteorological drought's sunny and dry period,even the soil heavy drought can happen.It had the greatest influence on the agriculture.展开更多
In order to investigate the temperature characteristics of wood during microwave(MW) treatments,optical fiber sensors were used to measure wood(Pinus sylvestris L. var. mongolica Litv.) temperatures. The results show ...In order to investigate the temperature characteristics of wood during microwave(MW) treatments,optical fiber sensors were used to measure wood(Pinus sylvestris L. var. mongolica Litv.) temperatures. The results show that the development of internal temperatures in wood basically includes two patterns during the process of MW treatment. The first may be divided into three phases: warming, constant temperature, and a sharply rising phase. The second pattern may be divided into two phases: warming, and constant temperature. The maximum temperature(MT) and rate of temperature increase(RTI)rose as the microwave power increased. The initial wood moisture content decreased while the period of constant temperature fell. Temperatures varied in different positions in the wood. The order of MT and RTI levels were the upper surface, center, bottom surface and the end point.Along the direction of wood thickness, the closer the monitoring point was to the generator, the faster the temperature increased. The MT and RTI of the end point was a minimum value because of the rapid removal of steam.展开更多
文摘[ Objective] The study was to compare the structural and moisture characteristics of leaf from the plantlets of three types of omamental lily( Lilium brownii). [ Method ] The paraffin sections of leaves of tested lily varieties were prepared and then observed under microscope, and the stomatal characteristics and moisture characteristics of tested lily varieties were measured. I Resaltl All the three ornamental lily varieties show isobilateral leaf, single layer of epicuticula and lower epidermis, and no obvious differentiation of palisade tissue and spongy tissue; their stomata distribute in lower epidermis, and the guard cells are dumbbell-shaped; all of these matedais present high moisture. For the leaf sick- ness, midrib sickness and mesophyll tissue sickness, the order was determined to be oriental lily 〉 Lilium/ongiflorum 〉 Asian lily; of the three types of ornamental lily, Ulium Iongiflorum has the largest stomatai aperture and Asian lily has the smallest; focusing the water potential and moisture, the turn was Asian lily 〉 oriental lily 〉 Lilium Iong'fflorum. [ Condusion] The study may facilitate the artificial regulation of the growth conditions of the plantlets of ornamental lily.
基金This paper was supported by Chinese 863 Plan Water-Saving Agriculture (2002AA2Z4321),the Key Knowledge Innovation Project (SCXZY0103) and The Tenth-five Plan of Liaoning Province (2001212001).
文摘Robinia pseudoacacia stands act as a typical ecological protection forest in hilly semi-arid area of China. Two fields of surface runoff were separately set up in R. pseudoacacia stand and its clearcut area in the western Liaoning Province (1850-12225 E, 4024-4234 N) for measuring the characteristics of runoff and sediment as well as soil moisture dynamics. Contractive analysis of the two land types showed that there existed a significant difference in volumes of runoff and sediment between the sites of R. pseudoacacia stand and its clearcut area. The runoff volume and sediment volume in clearcut area were much bigger than those in R. pseudoacacia stand, with an increase amount of 40%-177% for runoff and 180%-400% for sediment. Hydrograph of surface runoff of typical rainfall showed that the peak value of runoff in R. pseudoacacia stand was decreased by 1.0-2.5?0-3m3s-1 compared with that in its clearcut area, and the occurring time of peak value of runoff in R. pseudoacacia stand was 10-20 min later than that in its clearcut area. Harmonic analysis of soil moisture dynamics indicated that the soil moisture in R. pseudoacacia stand was 2.3 % higher than that in clearcut area, and the soil moisture both in R. pseudoacacia stand and its clearcut area could be divided into dry season and humid season and varied periodically with annual rainfall precipitation. It was concluded that R. pseudoacacia stand plays a very important role in storing water, increasing soil moisture, and reducing surface runoff and soil erosion.
基金Supported by National Key Program of Science and Technology(2011BAC09B01,2006BAC01A16)Natural Science Foundation Project of Chongqing(CSTC,2009BA0002)~~
文摘Ecological efficiency changes of soil moisture were researched in karst areas with different land type uses, including farmland, abandoned farmland (1 y) and shrub land (1 y), sparse wood land (15 y), secondary forest (25 y) and the re- sults showed that physical property of soil was not a simple "improvement" process during land type evolution. Specifically, from farmland to secondary forest, the con- tent of topsoils changed from being washed away to accumulation and soil bulk density changed from increasing to decreasing. For example, soil bulk densities of abandoned farmland and shrub land increased by 6.6% and 11.57% compared with farmland, and of sparse wood land and forest land decreased by 5.0% and 10.0%. The change trend of soil bulk density was just in contrary to total porosity. Available water capacity was the lowest of shrub land, but increased in rest land types. The increase tended to be volatile in 5.1%-12.5% of different land types and water-sta- ble aggregate content (〉0.25 mm) reached the highest of sparse wood land. The destruction rate, however, was declining in the process of land type evolution and the increase was in the range of 34.0%-64.7% compared with farmland. The de- struction rate of aggregate was of negative correlation with organic matter. Water- holding capacity was the best of forest land and abandoned farmland and the poor- est of shrub land, close to sparse wood land. Water-supplying capacity from high to low was as follows: farmland〉sparse wood land〉secondary forest〉shrub land〉a- bandoned farmland. It is obvious that water-holding capacity and water-supplying capacity are not consistent, but both are closely related to the content of soil clays, porosity, and aggregate stability.
基金supported by National Science Foundation of China (No.31270374)Independent Innovation Foundation of Shandong University (No.2011DX008)+1 种基金Natural Science Foundation of Shandong Province,China (No.2009ZRB01875ZR2010CM062)
文摘We investigated the combined effects of soil moisture and light intensity on the growth, development and ecophysiological characteristics of one-year old Amorpha fruticosa seedlings. Soil moisture and light intensity influenced the ecophysiological characteristics of Amorpha fruticosa seedlings. Soil moisture resulted in the decreases of growth rate, individual size, net photosynthetic rate, transpiration rate, leaf water loss rate (WLR), and biomass accumulation of plant parts, and led to increased leaf water saturation deficit (WSD). Under water stress, more photosynthetic products were allocated to root growth. With decreasing light intensity, net photosynthetic rate, transpiration rate, chla/b, water saturation deficit, water use efficiency, water loss rate and biomass accumulation declined, while Chla, Chlb, Chla+b and carotenoids (Car) increased and more photosynthetic products were allocated to stem and leaf growth. Maximum growth vigor, net photosynthetic rate and total biomass accumulation in Amorpha fruticosa seedlings was recorded at 75 80% soil water-holding capacity and 100% light density in greenhouse environments.
基金sponsored by "973" Program No. 2006CB403604National Technol-ogy Support Program (2007BAC03A01)the National Natural Science Foundation of China under Grant Nos.40531006 and 40576012
文摘The climatological characteristics of the moisture budget over the joining area of Asia and the IndianPacific Ocean (AIPO) and its adjacent regions as well as their anomalies have been estimated in this study. The main results are as follows. In the winter, the northeasterly moisture transport covers the extensive areas at the lower latitudes of the AIPO. The westerly and northerly moisture transport is the major source and the South Indian Ocean (SIO) is the moisture sink. In the summer, influenced by the southwesterly monsoonal wind, the crossequatorial southwesterly moisture transport across Somali originating from the SIO is transported through the Arabian Sea (AS), the Bay of Bengal (BOB), and the South China Sea (SCS) to eastern China. The AIPO is controlled by the southwesterly moisture transport. The net moisture influx over the AIPO has obvious interannual and interdecadal variations. From the mid- or late 1970s, the influxes over the SIO, the AS, the northern part of the western North Pacific (NWNP), and North China (NC) as well as South China (SC) begin to decrease abruptly, while those over Northeast China (NEC) and the Yangtze River-Huaihe River basins (YHRB) have increased remarkably. As a whole, the net moisture influxes over the BOB and the southern part of the western North Pacific (SWNP) in the recent 50 years take on a linear increasing trend. However, the transition timing for these two regions is different with the former being at the mid- or late 1980s and the latter occurring earlier, approximately at the early stage of the 1970s. The anomalous moisture source associated with the precipitation anomalies is different from the normal conditions of the summer precipitation. For the drought or flood years or the years of E1 Nifio and its following years, the anomalous moisture transport originating from the western North Pacific (WNP) is the vital source of the anomalous precipitation over eastern China, which is greatly related with the variation of the subtropical Pacific high.
基金Tenth Five-year Plan of the Committee of the Science and Technology of Heilongjiang Province (GB02B4040-1)Item of Heilongjiang Education Bureau (10511012)
文摘An experiment about rice milling was made to study on the relationship between the different moisture content of brown rice and the energy consumption, the broken rice rate, the crack rate and the head rice yield. It could be concluded that the head rice yield increased at first falls and then along with the raise of moisture content and it could reach the maximum 70.78% when moisture content was 15.5%; the energy consumption of rice milling decreased along with the increase of moisture contents; the broken rice rate fell at first and then increased along with the raise of moisture contents and it could reach the minimum 4.28% when the moisture content was 15.5%.
基金Sponsored by the Key Technologies Research and Development Program of China(Grant No.2016YFB0600203).
文摘The effects of moisture content on the combustion characteristics and pore structure change of coal slime are studied in this paper.The effect of moisture content on the bed temperature change,combustion efficiency,and NO_(x)and SO_(2)emission were obtained in a bench⁃scale fluidized bed reactor,revealing that the lowest bed temperature decreases with the increase in moisture content,but the effect on the highest bed temperature is not the same.Moreover,with the increase in moisture content,the observed degree of blackening of the flue gas increased,and more CO was produced,which in turn leads to a lower combustion efficiency of the coal slime.However,the presence of moisture plays a positive role in the reduction of NO_(x)and SO_(2).With the increase in moisture content,the amount of NO_(x)and SO_(2)produced tends to decrease.The effect of water on the combustion process of slime is mostly the impact of the severe vaporization process in the early stage to form a large water vapor channel,which is beneficial to the evaporation and loss of water,conducive to the reaction of water and coal combustion products,such as the formation of CO,reduction of NO_(x),SO_(2),etc.The large holes formed by the impact of water vapor decreased with the decrease of moisture content,and the nanoscale pores are mostly caused by the combustion process of volatilization and coke formation after the end of vaporization,and increase with the decrease of moisture content.
基金Part One in Development Planning for National Key Fundamental Research (G1998040900)"South China Sea Monsoon Experiment Studies"caling Project A of National Ministry of Science and Technology
文摘Apparent moisture sink and water vapor transport flux are calculated by using NCAR/NCEP reanalyzed daily data for water vapor and wind fields at various levels from 1980 to 1989.With the aid of EOF analysis method,temporal and spatial characteristics of moisture budgets over Asian and Australian monsoon regions are studied.The results show that there is apparent seasonal transition of moistrue sink and water vapor transport between Asian monsoon region and Australian monsoon region.In winter,the Asian monsoon region is a moisture source,in which three cross-equatorial water vapor transport channels in the 'continent bridge',at 80°E and 40°E~50° transport water vapor to the Australian monsoon region and southern Indian Ocean which are moistrue sinks.In summer,Australian Monsoon region anmd southern Indian Ocean are moistrue sources and by the three cross-equatorial transport channels water vapor is transport to the Asian monsoon region which is a moisture sink.In spring and autumn,ITCZ is the main moisture sink and there is no apparent water vapor transport between Asian monsoon region and Australian monsoon region.
文摘This study investigates the impact of soil moisture availability on dispersion-related characteristics: surface friction velocity (u* ), characteristic scales of temperature and humidity (T * and q * ), the planetary boundary layer height (h) and atmospheric stability classified by Monin-Obukhov length (L), Kazanski-Monin parameter (μ) and convective velocity scale (w* ) during daytime convective condition using a one-dimensional primitive equation with a refined soil model.
文摘Soil moisture (SM) is one of the important parameters in the process of land-atmosphere interactions. The spatial-temporal distribution of SM plays a significant role in weather and climate research. In this study, based on the monthly SM datasets from GLDAS (Global Land Surface Data Assimilation System), the temporal and spatial changes of shallow SM are discussed, and the applicability of five domestic models from Coupled Model Intercomparison Project 6 (CMIP6) is also evaluated in the Northwest China. The results show that: 1) The shallow SM (0 - 10 cm) in spring in Northwest China was generally low during 1948-2015, and the low value areas were mainly located in the Tarim Basin in Xinjiang and the Gobi and desert areas in western Inner Mongolia. In most parts of Northwest China, SM had an increasing trend in spring, this implies it became wetter in recent 60 years;2) There are larger difference between the five models for simulating SM. Except for BCC-ESM1, all the four models (including BCC-CSM2-MR, FGOALS-f3-L, FGOALS-g3, TaiESM1) can basically simulate the spatial distribution and trend of SM in spring, all the spatial correlation coefficients between the four models and GLDAS data pass the 99% significant level;3) After multi-ensemble mean, the simulation performance can be obviously improved, the spatial correlation can reach about 0.55 in spring, the spatial trend is much closer to the GLDAS.
基金supported by President’s Scholarships from the University of South Australia towards his PhD study。
文摘Climate change is one of the major global challenges and it can have a significant influence on the behaviour and resilience of geotechnical structures.The changes in moisture content in soil lead to effective stress changes and can be accompanied by significant volume changes in reactive/expansive soils.The volume change leads to ground movement and can exert additional stresses on structures founded on or within a shallow depth of such soils.Climate change is likely to amplify the ground movement potential and the associated problems are likely to worsen.The effect of atmospheric boundary interaction on soil behaviour has often been correlated to Thornthwaite moisture index(TMI).In this study,the long-term weather data and anticipated future projections for various emission scenarios were used to generate a series of TMI maps for Australia.The changes in TMI were then correlated to the depth of suction change(H s),an important input in ground movement calculation.Under all climate scenarios considered,reductions in TMI and increases in H s values were observed.A hypothetical design scenario of a footing on expansive soil under current and future climate is discussed.It is observed that a design that might be considered adequate under the current climate scenario,may fail under future scenarios and accommodations should be made in the design for such events.
文摘A soil water retention curve (SWRC) is an essential soil physical property for analyzing transport and retention of water in a soil layer. A SWRC is often described as a single-valued function that relates the soil water potential ψ to volumetric water content θ of the soil. However, an in-situ ψ − θ relation should show soil water hysteresis, though this fact is often neglected in analyses of field soil water regimes while long-term in-situ soil water hysteresis is not well characterized. This study aimed at probing and characterizing in-situ ψ − θ relations. The developments of large hysteresis in the in-situ ψ − θ relations were observed only a few times during the study period of 82 months. Any of the large hysteretic behaviors in the ψ − θ relations began with an unusually strong continual reduction in ψ. The completion of a hysteresis loop required a recorded maximum rainfall. Because the study field had very small chances to meet such strong rainfall events, it took multiple years to restore the fraction of soil water depleted by the unusually strong continual reduction in ψ. While wetting-drying cycles had occurred within a certain domain of ψ, hysteretic behaviors tended to be so small that the in-situ ψ − θ relation can be approximated as a single-valued function of θ(ψ). These observed patterns of the in-situ ψ − θ relations were characterized by kinds of difference in dθ/dψ between a drying process and a wetting process at a given ψ. Thus, more amounts of experimental facts about wetting SWRCs in parallel with drying SWRCs should be needed for correct modelling, analyzing, and predicting soil water regimes in fields. It is also necessary to increase our understandings about the long-term trends of occurrences of extreme weather conditions associated with possible change in climate.
文摘On the basis of discussing the influencing mode of plant moisture stress on plant physiological process and the division of soil moisture availability range, the water suction values partitioning soil moisture were put forward, and then the corresponding water moistures under water stress were obtained by conversing together with characteristic curve of water moisture.
文摘For obtaining the drying curve of powder under fluidized drying, a normal fluidized-bed dryer is designed to study the drying kinetics of PVC (polyvinyl chloride) powder in the experiment. A new measure system is derived for drying dynamics testing. In the small fluidized-bed dryer, fluidization parameter of PVC powder is tested, and the operating air velocity can be chosen in the range of 0. 41 to 0. 55 m/s. Accordingly, the fluidized number Ua/Umf is from 1.24 to 1.67. A promising drying model is used to describe the drying process, and then the characteristic drying curve of PVC powder derived from a suspension method can be expressed as f = [-0. 622 6 + 1. 254 6exp(2. 561 5Φ -0. 707 2) /[1 + exp(2. 561 5Φ -0. 707 2)] Based on the experiments, the critical moisture content xc and the mass transfer coefficient K are determined to be 0. 02 kg/kg and 6. 0 × 10^-4 kg/( m2 · s), respectively. The experimental results in the small fluidized-bed dryer are similar to those of the real fluidized drying process, so the descried method can also be used in determining drying kinetics of powder materials such as PVC powder.
基金Supported by the National Natural Science Foundation of China(40801100,50179035,50609022)the State Key Laboratory Fund Project of Soil Erosion and Dryland Faming on Loess Plateau(10501-177,10501-220)+1 种基金the Discipline Construction Fund of Ludong Universitythe Open Fund for Key Laboratory of Soil,Water and Environmental Conservation in Shandong Province(STKF201011)~~
文摘[Objective] The aim was to study the effect of salt solution on characteristics of soil infiltration, and to provide references for the further studies on the effect of water quality on soil infiltration characteristics and its mechanism. [Method] With the NaCl, CaCl2 solutions as the main test materials, the effect of different water quality and salt solution concentration on soil infiltration was studied under one-dimensional vertical ponded water infiltration at laboratory. [Result] The solution concentration could affect the infiltration performance. The trends of the infiltration rates, cumulative infiltrations and wetting front migration distances were all 50 mg/L 100 mg/L 10 mg/L. At the same concentration, the effect of NaCl solution on soil infiltration characteristics was more significant than CaCl2 solution: in the same time, cumulative infiltration and wetting front migration distance of NaCl solution were greater than CaCl2 solution; compared with NaCl solution, CaCl2 solution took longer time to infiltrate the same amount of water. The dynamic changes of infiltration rate, wetting front and cumulative infiltration were well fitted to the Philip model. [Conclusion] This study only conducted indoor experiment to the infiltration of salt solutions, involving in low concentration and small range. Although it provided some references for the study on the effect of water quality on soil infiltration characteristics and its mechanism, studies in larger areas and with bigger concentrations are demanding.
基金Project supported by the State Key Development Program for Basic Research of China(Grant Nos.2013CB430204 and 2012CB955902)the National Natural Science Foundation of China(Grant Nos.41175067,41175084,and 41205040)
文摘In this paper, we study the spatiotemporal characteristics of precipitable water, precipitation, evaporation, and watervapor flux divergence in different seasons over northeast China and the water balance of that area. The data used in this paper is provided by the European Center for Medium-Range Weather Forecasts (ECMWF). The results show that the spatial distributions of precipitable water, precipitation, and evaporation feature that the values of elements above in the southeastern area are larger than those in the northwestern area; in summer, much precipitation and evaporation occur in the Changbai Mountain region as a strong moisture convergence region; in spring and autumn, moisture divergence dominates the northeast of China; in winter, the moisture divergence and convergence are weak in this area. From 1979 to 2010, the total precipitation of summer and autumn in northeast China decreased significantly; especially from 1999 to 2010, the summer precipitation always demonstrated negative anomaly. Additionally, other elements in different seasons changed in a truly imperceptible way. In spring, the evaporation exceeded the precipitation in northeast China; in summer, the precipitation was more prominent; in autumn and winter, precipitation played a more dominating role than the evaporation in the northern part of northeast China, while the evaporation exceeded the precipitation in the southern part. The Interim ECMWF Re-Analysis (ERA-Interim) data have properly described the water balance of different seasons in northeast China. Based on ERA-Interim data, the moisture sinks computed through moisture convergence and moisture local variation are quite consistent with those computed through precipitation and evaporation, which proves that ERA- Interim data can be used in the research of water balance in northeast China. On a seasonal scale, the moisture convergence has a greater influence than the local moisture variation on a moisture sink, and the latter is variable slightly, generally as a constant. Likewise, in different seasons, the total precipitation has a much greater influence than the evaporation on the moisture sink.
文摘The effect of vertical internal baffles on the particle mixing and graindrying characteristics in a batch fluidized bed column is investigated. Experimental work wascarried out in a 3m high rectangular fluidized bed dryer of cross sectional area of 0.15 m x 0.61 mat different operating conditions using paddy, a group D particle, as the fluidizing material. Theresults of the study showed that the fluidized bed dryer system with vertical internal baffles gavebetter particle mixing effect in the bed of particles than that without vertical internal baffles.This is due to the fact that the vertical internal baffle act as gas bubble breakers by breaking upthe large gas bubbles into smaller ones. The smaller bubbles cause a more vigorous mixing in the bedof particles before finally erupting at the bed surface. This improves the contacting efficiencyand enhanced the heat and mass transfer of the fluidized bed system. Thus a higher drying rate wasobtained in the falling rate period because the higher contacting efficiency increases theevaporation rate at the particle surface. However, the drying rate in the diffusion region showslittle improvement because the moisture diffusivity does not depend on the contacting efficiency.The fluidized bed dryer with vertical internal baffles could therefore be used in the initial rapiddrying stage in a two stage drying strategy for paddy. The insertion of vertical internal bafflesinto a fluidized bed system improves the processing of Group D particles in a fluidized bed systemespecially if the system is large in scale.
文摘Multipurpose tree species (MPTs) were studied in an agroforestry arboretum under subtropical humid climate in Northeast India. Out of 12 MPTs planted under agroforestry systems, Acacia auriculiformis in spacing of 2 m × 2 m (2500 stems·hm^-2) could have the potentiality to meet the timber/fuelwood requirement due to its high wood production of 635 m^3·hm^-2 with mean annual increment (MAI) of 2.54×10^-2 m^3.treel.a^-1 in a short rotation period of 10 years. Thus, A. auriculiformis is a short rotation forest tree species suitable to grow in subtropical humid climate. On the other hand, at 16 years of age, Eucalyptus hybrid and Michelia champaca in spacing of 3 m × 3 m (1111 stems.hm^2) produced appreciably high timber volume of 315 m^3.hm^-2 and 165 m^3.hm^-2 with MAI of 1.77×10^-2 m^3.tree^-1·a^-1 and 0.92×10.2 m^3.tree^-1.a^-1, respectively. At 16 years of age, Gmelina arborea produced a timber volume of 147 m^3.hm^-2 with MAI of 1.47×10^-2 m^3.tree^-1.a^-1 followed by Samania saman (140 m^3.hm^-2), Albizziaprocera (113 m^3·hm^-2) and Tectona grandis (79 m3.hm^-2) with MAI of 1.40, 1.13 and 0.78 × 10^-2 m^3 .tree^-1a^-1, respectively in 4 m × 4 m spacing (625 stems.hm^-2). Gliricidia maculata and Leucaena leucocephala could be used as live fences around the farm boundary to supply their N-rich leaves for mulch as well as manure to crops. In agroforestry arboretum, direct seeded upland rice (Oryza sativa - variety, AR-11), groundnut (Arachis hypogaea - variety, JL-24) and sesamum (Sesamum indicum - variety, B-67) were grown during the initial period upto 8 years of tree establishment. Under other MPTs, there was a reduction in crop productivity as compared to open space. After 8 years of tree establishment, horti-silvi and silvi-pastoral systems were developed and pineapple (Ananas comosus - variety Queen), turmeric (Curcuma longa -variety RCT -1) and cowpea (Vigna sinensis - variety Pusa Barsati) as forage crop were raised. The productivity of pineapple, turmeric and cowpea was comparatively high under Azadirachta indica. The productivity of horticultural and forage crops in association with trees such as G. arborea, A. procera, S. saman, T. grandis and M. champaca of high timber value could be harnessed as viable agroforestry systems. Changes in soil properties were also monitored. Amelioration of soil acidity, increase in soil organic carbon, and enhanced humification of soil humus, high nutrient availability, low soil erodibility and high surface soil (0-15 cm) moisture availability were noted in soils under MPTs.
文摘The drought characteristics,the relationships between the drought and the meteorological factors,soil moisture content in Jinjiang City were analyzed.The results showed that Jinjiang belonged to the serious area which the drought occurred frequently.The summer drought occurrence frequency which was annual average 1.5 times was the highest.The droughts often occur in the continuous drought form,and the droughts which are above the great drought mainly occur in summer,fall and winter.Since 2000,the probabilities which spring drought and summer drought occurred in Jinjiang have reduced obviously.However,the probabilities which the continuous drought in summer,fall and fall,winter occurred have increased obviously.80% of droughts reached the special drought standard,and the drought disaster's times tended to aggravate and accelerate.The continuous drought days negatively correlated with the precipitation and positively correlated with the sunshine hours.The relativity was the highest.50% of meteorological droughts could cause the soil drought.However,the meteorological drought and the soil drought weren't synchronous.The soil moderate drought often happens in the meteorological drought's sunny and dry period,even the soil heavy drought can happen.It had the greatest influence on the agriculture.
基金financially supported by the National‘‘Twelfth Five-Year’’ Plan for Science&Technology(No.2015BAD14B04)the Special Fund for Forest Scientific Research in the Public Interest of China(No.201404516)
文摘In order to investigate the temperature characteristics of wood during microwave(MW) treatments,optical fiber sensors were used to measure wood(Pinus sylvestris L. var. mongolica Litv.) temperatures. The results show that the development of internal temperatures in wood basically includes two patterns during the process of MW treatment. The first may be divided into three phases: warming, constant temperature, and a sharply rising phase. The second pattern may be divided into two phases: warming, and constant temperature. The maximum temperature(MT) and rate of temperature increase(RTI)rose as the microwave power increased. The initial wood moisture content decreased while the period of constant temperature fell. Temperatures varied in different positions in the wood. The order of MT and RTI levels were the upper surface, center, bottom surface and the end point.Along the direction of wood thickness, the closer the monitoring point was to the generator, the faster the temperature increased. The MT and RTI of the end point was a minimum value because of the rapid removal of steam.