Some of the chemical and physical water qualities of the Graff River in the city of Kut were studied, and for two sites of the river, One was at the Crimea site, the other in the Jihad district, and for the period fro...Some of the chemical and physical water qualities of the Graff River in the city of Kut were studied, and for two sites of the river, One was at the Crimea site, the other in the Jihad district, and for the period from October/2018 to March/2019, Seven variables of river water have been analyzed: temperature PH, electrical conductivity, TDS, turbidity, alkaline, and chloride. The results showed that most of the chemical and physical water properties of the river were in normal proportions and did not rise, except for the turbidity, which was at a very high level, and that the pH values were close to the basal side. The results of the statistical analysis revealed positive significant relationships between the pH and (chloride and TDS). On the other hand, between electrical conductivity and both previous variables as well. And a negative significant connection between temperature and alkaline.展开更多
A second rain belt sometimes occurs ahead of a frontal rain belt in the warm sector over coastal South China,leading to heavy precipitation.We examined the differences in the mesoscale characteristics and microphysics...A second rain belt sometimes occurs ahead of a frontal rain belt in the warm sector over coastal South China,leading to heavy precipitation.We examined the differences in the mesoscale characteristics and microphysics of the frontal and warm sector rain belts that occurred in South China on May 10–13,2022.The southern rain belt occurred in an environment with favorable mesoscale conditions but weak large-scale forcing.In contrast,the northern rain belt was related to low-level horizontal shear and the surface-level front.The interaction between the enhanced southeasterly winds and the rainfall-induced cold pool promoted the persistent growth of convection along the southern rain belt.The convective cell propagated east over the coastal area,where there was a large temperature gradient.The bow-shaped echo in this region may be closely related to the rear-inflow jet.By contrast,the initial convection of the northern rain belt was triggered along the front and the region of low-level horizontal shear,with mesoscale interactions between the enhanced warm-moist southeasterly airflow and the cold dome associated with the earlier rain.The terrain blocked the movement of the cold pool,resulting in the stagnation of the frontal convective cell at an early stage.Subsequently,a meso-γ-scale vortex formed during the rapid movement of the convective cell,corresponding to an enhancement of precipitation.The representative raindrop spectra for the southern rain belt were characterized by a greater number and higher density of raindrops than the northern rain belt,even though both resulted in comparable hourly rainfalls.These results help us better understand the characteristics of double rain belts over South China.展开更多
The dynamic physical characteristics of a DC arc on an arcing horn for a high voltage direct current(HVDC)grounding electrode line are significantly different from those of the switching device arc,secondary arc,AC fa...The dynamic physical characteristics of a DC arc on an arcing horn for a high voltage direct current(HVDC)grounding electrode line are significantly different from those of the switching device arc,secondary arc,AC fault arc and pantograph-catenary arc.In this work,an experimental platform for the DC arc on the arcing horn was built,and mechanisms of the arc column short circuit and arc root movement were studied.This work further analyzes the characteristics and mechanisms of the arc motion when wind speed and direction,magnetic field and the expansion angle of the electrode are varied.Arc root movement is more likely to occur at the upper electrode.There is a competitive relationship between arc expansion and the transferring effect.The effect of wind on the arc column is greater than the effect on the arc root.The magnetic field has a significant driving effect on both the arc column and the arc root.The research results provide a comprehensive experimental basis for forther probing the method of DC arc suppression,and the improvement of the arcing horn.展开更多
With the increasing scarcity of Earth’s resources and the development of space science and technology,the exploration, development, and utilization of deep space-specific material resources(minerals, water ice, volat...With the increasing scarcity of Earth’s resources and the development of space science and technology,the exploration, development, and utilization of deep space-specific material resources(minerals, water ice, volatile compounds, etc.) are not only important to supplement the resources and reserves on Earth but also provide a material foundation for establishing extraterrestrial research bases. To achieve large depth in-situ condition-preserved coring(ICP-Coring) in the extreme lunar environment, first, lunar rock simulant was selected(SZU-1), which has a material composition, element distribution, and physical and mechanical properties that are approximately equivalent to those of lunar mare basalt. Second, the influence of the lunar-based in-situ environment on the phase, microstructure, and thermal physical properties(specific heat capacity, thermal conductivity, thermal diffusivity, and thermal expansion coefficient)of SZU-1 was explored and compared with the measured lunar rock data. It was found that in an air atmosphere, low temperature has a more pronounced effect on the relative content of olivine than other temperatures, while in a vacuum atmosphere, the relative contents of olivine and anorthite are significantly affected only at temperatures of approximately-20 and 200 ℃. When the vacuum level is less than100 Pa, the contribution of air conduction can be almost neglected, whereas it becomes dominant above this threshold. Additionally, as the testing temperature increases, the surface of SZU-1 exhibits increased microcracking, fracture opening, and unevenness, while the specific heat capacity, thermal conductivity,and thermal expansion coefficient show nonlinear increases. Conversely, the thermal diffusivity exhibits a nonlinear decreasing trend. The relationship between thermal conductivity, thermal diffusivity, and temperature can be effectively described by an exponential function(R^(2)>0.98). The research results are consistent with previous studies on real lunar rocks. These research findings are expected to be applied in the development of the test and analysis systems of ICP-Coring in a lunar environment and the exploration of the mechanism of machine-rock interaction in the in-situ drilling and coring process.展开更多
Warm-sector heavy rainfall(WR),shear-line heavy rainfall(SR),and frontal heavy rainfall(FR)are three types of rainfall that frequently occur during the pre-summer rainy season in south China.In this research,we invest...Warm-sector heavy rainfall(WR),shear-line heavy rainfall(SR),and frontal heavy rainfall(FR)are three types of rainfall that frequently occur during the pre-summer rainy season in south China.In this research,we investigated the differences in microphysical characteristics of heavy rainfall events during the period of 10-15 May 2022 based on the combined observations from 11 S-band polarimetric radars in south China.The conclusions are as follows:(1)WR has the highest radar echo top height,the strongest radar echo at all altitudes,the highest lightning density,and the most active ice-phase process,which suggests that the convection is the most vigorous in the WR,moderate in the FR,and the weakest in the SR.(2)Three types of rainfall are all marine-type precipitation,the massweighted mean diameter(Dm,mm)and the intercept parameter(Nw,mm^(-1) m^(-3))of the raindrops in the WR are the largest.(3)The WR possesses the highest proportion of graupel compared with the FR and SR,and stronger updrafts and more abundant water vapor supply may lead to larger raindrops during the melting and collision-coalescence processes.(4)Over all the heights,liquid and ice water content in the WR are higher than those in the SR and FR,the ratio of ice to liquid water content in the WR is as high as 27%when ZH exceeds 50 dBZ,definitely higher than that in the SR and FR,indicating that the active ice-phase process existing in the WR is conducive to the formation of heavy rainfall.展开更多
[Objective] The aim was to analyze physical structures of mixed cloud in autumn in Shandong.[Method] By dint of Doppler radar data,the raindrop spectrum data observed by laser spectrometer,second sounding data of L-ba...[Objective] The aim was to analyze physical structures of mixed cloud in autumn in Shandong.[Method] By dint of Doppler radar data,the raindrop spectrum data observed by laser spectrometer,second sounding data of L-band,satellite retrieval data,and other general information,the physical structures of mixed cloud in autumn on August 29,2009 were discussed.[Result] This was a typical precipitation process of mixed cloud,and the main precipitation process lasted for 10 hours.Rainfall intensity was ups and downs obviously with the time.The maximum rainfall intensity was 6.5 mm/h and the normal of that was less than 3.0 mm/h.The rain concentrations were between 5 and 300,and the raindrop spectrum was mainly of bimodal or multimodal peaks.It showed that the precipitating cloud was mainly cold cloud and the development of warm layers was not well according to the vertical structure of clouds which was analyzed by second sounding data.It showed by the Doppler radar data that the whole precipitation process was divided into four stages:prior period and initial,maturing,declining stages for precipitation,which the echo structure of different stages was quite different.[Conclusion] The study laid theoretical basis for the study on precipitation mechanism and artificial precipitation potential.展开更多
This article uses the literature data method and literature review method to review and collect relevant literature,and summarizes and analyzes the representative views on domestic physical fitness research.After summ...This article uses the literature data method and literature review method to review and collect relevant literature,and summarizes and analyzes the representative views on domestic physical fitness research.After summarizing and summarizing,it is considered that:physical energy is the basic athletic ability of the human body expressed through physical qualities such as strength,speed,endurance,coordination,flexibility,and sensitivity,and is an important component of athletes'athletic ability.The level of physical fitness is closely related to the morphological characteristics of the human body and the functional characteristics of the human body.The morphological characteristics of the human body are the structural basis of its physical fitness,and the functional characteristics of the human body are its biological functional basis.As the basic ability of athletes,physical fitness is an important factor of athletes'competitive ability.Each competitive sport has its own specific physical characteristics and training rules and methods.Grasping these laws has very important guiding significance for the improvement of athletes'sports level.展开更多
Using data of airborne particle measurement system, weather radar and Ka-band millimeter wave cloud-meter, physical structure characteristics of a typical stable stratiform cloud in Hebei Province on February 27, 2018...Using data of airborne particle measurement system, weather radar and Ka-band millimeter wave cloud-meter, physical structure characteristics of a typical stable stratiform cloud in Hebei Province on February 27, 2018 was analyzed. Research results showed that the detected cloud system was the precipitation stratiform cloud in the later stage of development. The cloud layer developed stably, and the vertical structure was unevenly distributed. The concentration of small cloud particles in high-level clouds was low, and it fluctuated greatly in space, and presented a discontinuous distribution state. The concentration of large cloud particles and precipitation particles was high, which was conducive to the growth of cloud droplets and the aggregation of ice crystals. The concentration of small cloud particles and the content of supercooled water were high in the middle and low-level clouds. The precipitation cloud system had a significant hierarchical structure, which conformed to the "catalysis-supply" mechanism. From the upper layer to the lower layer, the cloud particle spectrum was mainly in the form of single peak or double peak distribution, which showed a monotonic decreasing trend in general. The spectral distribution of small cloud particles in the cloud was discontinuous, and the high-value areas of spectral concentration of large cloud particles and precipitation particles were concentrated in the upper part of the cloud layer, and the particle spectrum was significantly widened. There was inversion zone at the bottom of the cloud layer, which was conducive to the continuous increase of particle concentration and the formation of large supercooled water droplets.展开更多
This paper seeks to identify macroscopic metallogenic mechanisms of various mineral deposits by studying microscopic typomorphic characteristics of typical minerals associated with the deposits and to reveal the mecha...This paper seeks to identify macroscopic metallogenic mechanisms of various mineral deposits by studying microscopic typomorphic characteristics of typical minerals associated with the deposits and to reveal the mechanism of lattice gold in detail by studying both physical and chemical characteristics of quartz from representative gold deposits in the North China Platform.As part of their extensive research,the authors examine the relationship between trace elements with wall rock,the ore-forming media,and gold immigration of various types of gold deposits,including their salinity,type,temperature.These are key factors to revealing the mineralization mechanism,and indicators for mineral prospecting,exploration,mining,and metallurgical technology.In order to address the questions posed,the following methods were used:field investigations of geology and sampling of the representative gold deposits,physical study and chemical analysis of quartz including,but not limited to,fluid inclusions as well as their compositions and trace elements in quartz,the unit cell parameters,electron paramagnetic resonance spectrum(EPR),and infrared spectroscopic analysis(ISA).As a result of this study,the authors observe the following key findings:unit cell parameters of quartz vary with their contents of foreign elements including gold,paragenetic stage,wall rock type,and other factors;the higher the forming temperature and the lower the gold content in quartz,the smaller the unit cell parameters,and vice versa.Additionally,the EPR absorption lines resulted from the O–Al defect center.The density of these types of hole centers increases and the EPR signal strengthens when the temperature decreases.Based on the findings,the authors conclude that lattice gold exists in quartz.Gold,in the form of Au^(+)and/or Au^(3+),entering quartz and producing an electron–hole center,namely,the O-Au hole center,makes the center produce spin resonance absorption and results in the EPR absorption peak#I.Both unit cell parameters and EPR of quartz can potentially be used in mineral prospecting,relative ore-forming temperature determination,and grade control during mining.展开更多
The existing research of welding arc mainly focuses on the stable combustion state and the research on the mechanism of welding arc ignition process is quite lack.The tungsten inert gas(TIG) touch arc ignition process...The existing research of welding arc mainly focuses on the stable combustion state and the research on the mechanism of welding arc ignition process is quite lack.The tungsten inert gas(TIG) touch arc ignition process is observed via a high speed camera and the high time resolution spectral diagnosis system.The changing phenomenon of main ionized element provided the electrons in the arc ignition is found.The metallic element is the main contributor to provide the electrons at the beginning of the discharging,and then the excitated shielding gas element replaces the function of the metallic element.The electron density during the period of the arc ignition is calculated by the Stark-broadened lines of Hα.Through the discussion with the repeatability in relaxation phenomenon,the statistical regularity in the arc ignition process is analyzed.The similar rules as above are observed through the comparison with the laser-assisted arc ignition experiments and the metal inert gas(MIG) arc ignition experiments.This research is helpful to further understanding on the generation mechanism of welding arc ignition and also has a certain academic and practical significance on enriching the welding physical theoretical foundation and improving the precise monitoring on automatic arc welding process.展开更多
Horticultural crops with the similar weight and uniform shape are in high demand in terms of marketing value that used as food. The knowledge on existing relationship among the mass, length, width, thickness, volume a...Horticultural crops with the similar weight and uniform shape are in high demand in terms of marketing value that used as food. The knowledge on existing relationship among the mass, length, width, thickness, volume and projected areas of fruits is useful for proper design of grading machines. A part of this research was aimed to present some physical properties of cherry fruit. In addition, in this study the mass of cherry fruit was predicted with using different physical characteristics in four models including: Linear, Quadratic, S-curve, and Power. According to the results, all properties considered in the current study were found to be statistically significant at the 1% probability level. The best and the worst models for mass prediction of cherry fruit were based on geometric mean diameter and thickness of the cherry with determination coefficients (R2) of 0.938 and 0.484, respectively. At last, mass model of cherry fruit based on first projected area from economical standpoint is recommended.展开更多
In order to diminish the effect of the ambient light and CCD pixel non-uniformity to the Precipitation Micro-physical Characteristics Sensor,a modified calibration scheme was designed and calibration experiments in su...In order to diminish the effect of the ambient light and CCD pixel non-uniformity to the Precipitation Micro-physical Characteristics Sensor,a modified calibration scheme was designed and calibration experiments in sunny,cloudy,night,different location of sample space were carried out. Firstly,the characteristics of particle images which affected by ambient light and different location of sample space were analyzed. Secondly,the relevance betw een particle image features and parameters of image processing were discussed. Finally,the parameter setting scheme were determined,the radium of median filtering algorithm is 3 pixels,the defocusing radius of point spread function( PSF) is 7 pixels,the radium of erosion is 3 pixels,and the binary threshold is obtained from the Area-thresh relationship. The results show that the new scheme could deal with the image calibration well,the average errors of equivolumetric diameter was 0. 041 mm with standard deviation of 0. 115 mm,and the average errors of the axis ratio was 0. 011 with standard deviation of 0. 085. The new scheme works well in the field observation too,the observed axis ratio is consistent with the empirical relationship that proposed by Beard. The relative error of accumulation precipitation is-3. 06% after calibration,w hich is improved 1. 94% low er than the initial one without calibration.展开更多
Tomato (Lycopersicon esculentum Mill) is quantitatively the highest vegetable consumed in Burkina Faso. The objective of this study was to evaluate the physico-chemical, nutritional characteristics, and sanitary quali...Tomato (Lycopersicon esculentum Mill) is quantitatively the highest vegetable consumed in Burkina Faso. The objective of this study was to evaluate the physico-chemical, nutritional characteristics, and sanitary quality of the tomato variety Mongal F1 from different production sites. Twenty-eight (28) samples of Mongal F1 fresh tomatoes were collected from 28 producers at three different localities of Ouahigouya, Loumbila and Ouagadougou. The physico-chemical and nutritional characteristics were determined by standardized methods and the traces metallic elements by atomic absorption spectrophotometry. The results revealed a degree brix varying from 4.07° to 5.50° and a pH ranging from 3.71 to 4.08 corresponding to a total acidity of 0.39% to 0.55% citric acid equivalents. The moisture content, the ash content, the total carbohydrates content, the reducing carbohydrates content, the lipids content and the protein content were ranged from 95.09% to 96.17%, 9.25% to 10.60%, 47.00% to 53.43%, 30.03% to 41.21%, 3.04% to 7.71% and 17.09% to 25.03% respectively. The results of the trace metals showed a high accumulation of total cadmium from 0.11 to 0.22 ppm, of total lead of 1.15 to 1.27 ppm and arsenic total of 0.19 to 0.20 ppm. The results proved that environmental conditions influence the quality of the tomato Mongal F1. Detection of trace elements in the tomato fruits suggests that a better production practices are needed.展开更多
The physiological properties of new compact vertical-leaf type varieties,such as corn Zhengdan 958,Xundan 18,Jidan 7,etc.were analyzed in order to provid references for its large extension and new high-yield breeding....The physiological properties of new compact vertical-leaf type varieties,such as corn Zhengdan 958,Xundan 18,Jidan 7,etc.were analyzed in order to provid references for its large extension and new high-yield breeding.Results showed that reasons of high-yield included reasonable indices of leaf-area changing,long keeping of corn leaves and slow aging.Photosynthetic pigment,protein and soluble sugar in varietal leaves were high with the high peroxide enzyme activation,photosynthesis inherent ability and photosynthesis eff iciency,but with low malondialdehyde.The volume of grain seed was big,with long forming or starch grouting time of cells and the weight of thousand-granules was high.It indicated that Zhengdan 958 was still the best corn variety for the extensive utilization.The seeds production should pay attention to keep the pure degree and the hallmark for giving full potential advantages on the yield of these species.展开更多
Study of petrophysical properties of rocks in seafloor hydrothermal fields has great significance for investigation of seafloor hydrothermal activities,especially for polymetallic sulfides prospecting.In the present s...Study of petrophysical properties of rocks in seafloor hydrothermal fields has great significance for investigation of seafloor hydrothermal activities,especially for polymetallic sulfides prospecting.In the present study,based on the current experimental conditions,we conducted systematic experiments to measure the magnetic susceptibility,electrical resistivity,porosity,density,as well as acoustic wave velocity of seafloor rocks and sulfides.Subsequently,we measured the physical characteristics of hydrothermal sulfides,basalts and peridotites which were collected from newly discovered seafloor hydrothermal fields at 49.6°E,50.5°E,51°E,63.5°E,and 63.9°E of the Southwest Indian Ridge(SWIR).Previously available and newly collected data were combined to characterize the physical differences between polymetallic sulfides and rocks.We also discussed the impact of hydrothermal alteration on the bedrock and demonstrated how these petrophysical properties of rocks can help in geophysical prospecting of seafloor hydrothermal fields as indicators.展开更多
Using standard and internationally validated methods,68 anthropologic characteristics were determined in 314 male(149 from Morin Dawa Daur Autonomous Banner and 165 from Tacheng)and 314 female(158 from Morin Dawa Daur...Using standard and internationally validated methods,68 anthropologic characteristics were determined in 314 male(149 from Morin Dawa Daur Autonomous Banner and 165 from Tacheng)and 314 female(158 from Morin Dawa Daur Autonomous Banner,156 from Tacheng)Chinese Daur adults living in Inner Mongolia Autonomous Region and Xinjiang Uygur Autonomous Region.The data were used to calculate 10 anthropologic indices,which were analyzed statistically.The physical characteristics of Daur subjects were analyzed and compared with reference ethnic data.There were some main findings of this study.展开更多
Flooding is becoming a yearly reoccurring event in many communities and cities in Nigeria, leading to the destruction of properties and deaths;hence, we must take measures to either prepare for the impact or curb the ...Flooding is becoming a yearly reoccurring event in many communities and cities in Nigeria, leading to the destruction of properties and deaths;hence, we must take measures to either prepare for the impact or curb the occurrence. The study identified flood vulnerability levels of communities in Isoko North LGA based on physical environmental domains such as land use, elevation, and proximity to river channel (drainage) using geospatial techniques. Also, attributes that could contribute to the resilience capacity building of the communities were assessed. From the study, 73.93% of the entire area is moderately and highly vulnerable to flood, while among the communities, seventeen (17) are categorized as moderately vulnerable, and four (4) are lowly vulnerable. The overall resilience capacity of the communities indicated can build a substantial capacity towards community resilience (3.02, 0.06). However, there is a need to encourage collaboration with stakeholders to improve mitigation action and enhance various shortcomings toward resilience capacity building.展开更多
Sustainable and appropriate watershed management strategies require the determination of biophysical information which includes the floral characteristics of the watershed. This study was conducted to characterize the...Sustainable and appropriate watershed management strategies require the determination of biophysical information which includes the floral characteristics of the watershed. This study was conducted to characterize the floral composition of the Bugang River watershed. Data gathering was done by conducting an inventory for trees, palms, and bamboos with Quadrant Sampling using a stratified random sampling method in the forested area of the watershed with 50 m × 20 m sampling plots. Floral species were identified and classified through local experts, published books, journals, the internet, and available references. A total of 60 species belonging to 31 families and 52 genera were found using this method. Gogo (Entada phaseoloides) had the highest number of species with 222 or 14% of the total species. Trees with dbh 10 cm and above have a total estimated volume of 102.31 m<sup>3</sup>. The average diameter and average height of species decrease as the elevation increases. The result showed that the Bugang River watershed has a diverse floral composition, with vertical stratification and a dense canopy. The advocacy and awareness campaign should be done and strengthen the protection and conservation efforts of concerned agencies for the sustainability of the watershed.展开更多
This work evaluates some physical parameters (the weight, length, diameter of fruits and seeds, number of seeds per fruit) and the effect of boiling and fermentation on the nutritional value of <em>Telfairia occ...This work evaluates some physical parameters (the weight, length, diameter of fruits and seeds, number of seeds per fruit) and the effect of boiling and fermentation on the nutritional value of <em>Telfairia occidentalis </em>(fluted pumpkin) seeds. Firstly, a survey was done in the city of Yaounde on the different treatments applied to the seeds before cooking. From the results of the survey, the seeds were divided into three groups: raw, boiled and fermented. The moisture, lipid, protein, fibre, carbohydrate and ash contents were analysed using AOAC methods and minerals by atomic absorption spectrophotometry. The results showed that <em>T. occidentalis</em> fruit averagely weighed 6.35 kg and contained about 90 seeds. The decorticated seeds had an ovoid shape, 3.70 cm long and weighed 8.91 g. Boiling led to an increase in lipid (16.29% - 31.44%) and carbohydrate (19.20% - 21.8%) but a decrease in protein (54.06% - 34.17%) contents. Fermentation increased the crude fibre (0.70% - 1.1%) but decreased the ash content (4.07% - 3.14% DM). Boiled seeds had higher calcium, magnesium, potassium and sodium, while fermented seeds had higher zinc levels. Boiling proved better in preserving most of the seed nutrients. These seeds could be used to prevent some mineral deficiencies and their high proteins suggest their potential for the formulation of infant foods.展开更多
The experiment compared the physical characteristics of aqua feed with crude or gelatinized tapioca starch as sources of energy.The bulk density(BD),water absorption index(WAI),water solubility index(WSI),pellet durab...The experiment compared the physical characteristics of aqua feed with crude or gelatinized tapioca starch as sources of energy.The bulk density(BD),water absorption index(WAI),water solubility index(WSI),pellet durability index(PDI)and water stability(WS)were measured in both experimental diets.The results showed significant variations(p<0.05)in BD and WAI in diet with crude tapioca starch while non-significant variations(p>0.05)were recorded for WSI and WS in both diets.The higher BD of a diet,the better its ability in resisting external forces that can cause disintegration.A high BD also reduces ability to the feed material shrinking,thereby preventing loss to feed dust and fines.The results of WSI,WS and PDI of diets denotes that both pellets were water stable and could spend about same time in water but diet with gelatinized starch had a better water absorption index and pellet durability index.Furthermore,proximate composition of diets showed that diets with gelatinized starch had low moisture(9.04%),low fibre(5.24%),and higher ash(13.61%)and lipid(9.64%)contents.It can be concluded from this experiment that diets with gelatinized starch stands the chance of being a better functional feed for small-scale fish farmers in Sub-Saharan Africa.展开更多
文摘Some of the chemical and physical water qualities of the Graff River in the city of Kut were studied, and for two sites of the river, One was at the Crimea site, the other in the Jihad district, and for the period from October/2018 to March/2019, Seven variables of river water have been analyzed: temperature PH, electrical conductivity, TDS, turbidity, alkaline, and chloride. The results showed that most of the chemical and physical water properties of the river were in normal proportions and did not rise, except for the turbidity, which was at a very high level, and that the pH values were close to the basal side. The results of the statistical analysis revealed positive significant relationships between the pH and (chloride and TDS). On the other hand, between electrical conductivity and both previous variables as well. And a negative significant connection between temperature and alkaline.
基金National Natural Science Foundation of China(41930972,52239006,41975001)。
文摘A second rain belt sometimes occurs ahead of a frontal rain belt in the warm sector over coastal South China,leading to heavy precipitation.We examined the differences in the mesoscale characteristics and microphysics of the frontal and warm sector rain belts that occurred in South China on May 10–13,2022.The southern rain belt occurred in an environment with favorable mesoscale conditions but weak large-scale forcing.In contrast,the northern rain belt was related to low-level horizontal shear and the surface-level front.The interaction between the enhanced southeasterly winds and the rainfall-induced cold pool promoted the persistent growth of convection along the southern rain belt.The convective cell propagated east over the coastal area,where there was a large temperature gradient.The bow-shaped echo in this region may be closely related to the rear-inflow jet.By contrast,the initial convection of the northern rain belt was triggered along the front and the region of low-level horizontal shear,with mesoscale interactions between the enhanced warm-moist southeasterly airflow and the cold dome associated with the earlier rain.The terrain blocked the movement of the cold pool,resulting in the stagnation of the frontal convective cell at an early stage.Subsequently,a meso-γ-scale vortex formed during the rapid movement of the convective cell,corresponding to an enhancement of precipitation.The representative raindrop spectra for the southern rain belt were characterized by a greater number and higher density of raindrops than the northern rain belt,even though both resulted in comparable hourly rainfalls.These results help us better understand the characteristics of double rain belts over South China.
基金National Natural Science Foundation of China(No.51907168)funded by Sichuan Science and Technology Program(Outstanding Youth Science and Technology Talents)(No.2020JDJQ0039)。
文摘The dynamic physical characteristics of a DC arc on an arcing horn for a high voltage direct current(HVDC)grounding electrode line are significantly different from those of the switching device arc,secondary arc,AC fault arc and pantograph-catenary arc.In this work,an experimental platform for the DC arc on the arcing horn was built,and mechanisms of the arc column short circuit and arc root movement were studied.This work further analyzes the characteristics and mechanisms of the arc motion when wind speed and direction,magnetic field and the expansion angle of the electrode are varied.Arc root movement is more likely to occur at the upper electrode.There is a competitive relationship between arc expansion and the transferring effect.The effect of wind on the arc column is greater than the effect on the arc root.The magnetic field has a significant driving effect on both the arc column and the arc root.The research results provide a comprehensive experimental basis for forther probing the method of DC arc suppression,and the improvement of the arcing horn.
基金supported by the National Natural Science Foundation of China(Nos.U2013603 and 52225403)the Program for Guangdong Introducing Innovative and Entrepreneurial Teams(No.2019ZT08G315)the Shenzhen National Science Fund for Distinguished Young Scholars(No.RCJC20210706091948015).
文摘With the increasing scarcity of Earth’s resources and the development of space science and technology,the exploration, development, and utilization of deep space-specific material resources(minerals, water ice, volatile compounds, etc.) are not only important to supplement the resources and reserves on Earth but also provide a material foundation for establishing extraterrestrial research bases. To achieve large depth in-situ condition-preserved coring(ICP-Coring) in the extreme lunar environment, first, lunar rock simulant was selected(SZU-1), which has a material composition, element distribution, and physical and mechanical properties that are approximately equivalent to those of lunar mare basalt. Second, the influence of the lunar-based in-situ environment on the phase, microstructure, and thermal physical properties(specific heat capacity, thermal conductivity, thermal diffusivity, and thermal expansion coefficient)of SZU-1 was explored and compared with the measured lunar rock data. It was found that in an air atmosphere, low temperature has a more pronounced effect on the relative content of olivine than other temperatures, while in a vacuum atmosphere, the relative contents of olivine and anorthite are significantly affected only at temperatures of approximately-20 and 200 ℃. When the vacuum level is less than100 Pa, the contribution of air conduction can be almost neglected, whereas it becomes dominant above this threshold. Additionally, as the testing temperature increases, the surface of SZU-1 exhibits increased microcracking, fracture opening, and unevenness, while the specific heat capacity, thermal conductivity,and thermal expansion coefficient show nonlinear increases. Conversely, the thermal diffusivity exhibits a nonlinear decreasing trend. The relationship between thermal conductivity, thermal diffusivity, and temperature can be effectively described by an exponential function(R^(2)>0.98). The research results are consistent with previous studies on real lunar rocks. These research findings are expected to be applied in the development of the test and analysis systems of ICP-Coring in a lunar environment and the exploration of the mechanism of machine-rock interaction in the in-situ drilling and coring process.
基金National Natural Science Foundation of China(U2242203,41975138,41905047,42030610)the High-level Science and Technology Journals Projects of Guangdong Province(2021B1212020016)+2 种基金Natural Science Foundation of Guangdong Province(2019A1515010814,2021A1515011415)Science and Technology Research Project of Guangdong Meteorological Bureau(GRMC2020M01)the Joint Research Project for Meteorological Capacity Improvement(22NLTSQ003)。
文摘Warm-sector heavy rainfall(WR),shear-line heavy rainfall(SR),and frontal heavy rainfall(FR)are three types of rainfall that frequently occur during the pre-summer rainy season in south China.In this research,we investigated the differences in microphysical characteristics of heavy rainfall events during the period of 10-15 May 2022 based on the combined observations from 11 S-band polarimetric radars in south China.The conclusions are as follows:(1)WR has the highest radar echo top height,the strongest radar echo at all altitudes,the highest lightning density,and the most active ice-phase process,which suggests that the convection is the most vigorous in the WR,moderate in the FR,and the weakest in the SR.(2)Three types of rainfall are all marine-type precipitation,the massweighted mean diameter(Dm,mm)and the intercept parameter(Nw,mm^(-1) m^(-3))of the raindrops in the WR are the largest.(3)The WR possesses the highest proportion of graupel compared with the FR and SR,and stronger updrafts and more abundant water vapor supply may lead to larger raindrops during the melting and collision-coalescence processes.(4)Over all the heights,liquid and ice water content in the WR are higher than those in the SR and FR,the ratio of ice to liquid water content in the WR is as high as 27%when ZH exceeds 50 dBZ,definitely higher than that in the SR and FR,indicating that the active ice-phase process existing in the WR is conducive to the formation of heavy rainfall.
基金Supported by National Science and Technology Support Program (2006BAC12B07,2006BAC12B02)Shandong Meteorological Bureau Meteorological Insurance Service Program for 11th National Games (qyhqx14)
文摘[Objective] The aim was to analyze physical structures of mixed cloud in autumn in Shandong.[Method] By dint of Doppler radar data,the raindrop spectrum data observed by laser spectrometer,second sounding data of L-band,satellite retrieval data,and other general information,the physical structures of mixed cloud in autumn on August 29,2009 were discussed.[Result] This was a typical precipitation process of mixed cloud,and the main precipitation process lasted for 10 hours.Rainfall intensity was ups and downs obviously with the time.The maximum rainfall intensity was 6.5 mm/h and the normal of that was less than 3.0 mm/h.The rain concentrations were between 5 and 300,and the raindrop spectrum was mainly of bimodal or multimodal peaks.It showed that the precipitating cloud was mainly cold cloud and the development of warm layers was not well according to the vertical structure of clouds which was analyzed by second sounding data.It showed by the Doppler radar data that the whole precipitation process was divided into four stages:prior period and initial,maturing,declining stages for precipitation,which the echo structure of different stages was quite different.[Conclusion] The study laid theoretical basis for the study on precipitation mechanism and artificial precipitation potential.
文摘This article uses the literature data method and literature review method to review and collect relevant literature,and summarizes and analyzes the representative views on domestic physical fitness research.After summarizing and summarizing,it is considered that:physical energy is the basic athletic ability of the human body expressed through physical qualities such as strength,speed,endurance,coordination,flexibility,and sensitivity,and is an important component of athletes'athletic ability.The level of physical fitness is closely related to the morphological characteristics of the human body and the functional characteristics of the human body.The morphological characteristics of the human body are the structural basis of its physical fitness,and the functional characteristics of the human body are its biological functional basis.As the basic ability of athletes,physical fitness is an important factor of athletes'competitive ability.Each competitive sport has its own specific physical characteristics and training rules and methods.Grasping these laws has very important guiding significance for the improvement of athletes'sports level.
基金Supported by National Key R&D Plan Projects (2018YFC1507900)Hebei Province Science and Technology Plan Program(20375402D)。
文摘Using data of airborne particle measurement system, weather radar and Ka-band millimeter wave cloud-meter, physical structure characteristics of a typical stable stratiform cloud in Hebei Province on February 27, 2018 was analyzed. Research results showed that the detected cloud system was the precipitation stratiform cloud in the later stage of development. The cloud layer developed stably, and the vertical structure was unevenly distributed. The concentration of small cloud particles in high-level clouds was low, and it fluctuated greatly in space, and presented a discontinuous distribution state. The concentration of large cloud particles and precipitation particles was high, which was conducive to the growth of cloud droplets and the aggregation of ice crystals. The concentration of small cloud particles and the content of supercooled water were high in the middle and low-level clouds. The precipitation cloud system had a significant hierarchical structure, which conformed to the "catalysis-supply" mechanism. From the upper layer to the lower layer, the cloud particle spectrum was mainly in the form of single peak or double peak distribution, which showed a monotonic decreasing trend in general. The spectral distribution of small cloud particles in the cloud was discontinuous, and the high-value areas of spectral concentration of large cloud particles and precipitation particles were concentrated in the upper part of the cloud layer, and the particle spectrum was significantly widened. There was inversion zone at the bottom of the cloud layer, which was conducive to the continuous increase of particle concentration and the formation of large supercooled water droplets.
文摘This paper seeks to identify macroscopic metallogenic mechanisms of various mineral deposits by studying microscopic typomorphic characteristics of typical minerals associated with the deposits and to reveal the mechanism of lattice gold in detail by studying both physical and chemical characteristics of quartz from representative gold deposits in the North China Platform.As part of their extensive research,the authors examine the relationship between trace elements with wall rock,the ore-forming media,and gold immigration of various types of gold deposits,including their salinity,type,temperature.These are key factors to revealing the mineralization mechanism,and indicators for mineral prospecting,exploration,mining,and metallurgical technology.In order to address the questions posed,the following methods were used:field investigations of geology and sampling of the representative gold deposits,physical study and chemical analysis of quartz including,but not limited to,fluid inclusions as well as their compositions and trace elements in quartz,the unit cell parameters,electron paramagnetic resonance spectrum(EPR),and infrared spectroscopic analysis(ISA).As a result of this study,the authors observe the following key findings:unit cell parameters of quartz vary with their contents of foreign elements including gold,paragenetic stage,wall rock type,and other factors;the higher the forming temperature and the lower the gold content in quartz,the smaller the unit cell parameters,and vice versa.Additionally,the EPR absorption lines resulted from the O–Al defect center.The density of these types of hole centers increases and the EPR signal strengthens when the temperature decreases.Based on the findings,the authors conclude that lattice gold exists in quartz.Gold,in the form of Au^(+)and/or Au^(3+),entering quartz and producing an electron–hole center,namely,the O-Au hole center,makes the center produce spin resonance absorption and results in the EPR absorption peak#I.Both unit cell parameters and EPR of quartz can potentially be used in mineral prospecting,relative ore-forming temperature determination,and grade control during mining.
基金supported by National Natural Science Foundation of China(Grant No. 50375005)
文摘The existing research of welding arc mainly focuses on the stable combustion state and the research on the mechanism of welding arc ignition process is quite lack.The tungsten inert gas(TIG) touch arc ignition process is observed via a high speed camera and the high time resolution spectral diagnosis system.The changing phenomenon of main ionized element provided the electrons in the arc ignition is found.The metallic element is the main contributor to provide the electrons at the beginning of the discharging,and then the excitated shielding gas element replaces the function of the metallic element.The electron density during the period of the arc ignition is calculated by the Stark-broadened lines of Hα.Through the discussion with the repeatability in relaxation phenomenon,the statistical regularity in the arc ignition process is analyzed.The similar rules as above are observed through the comparison with the laser-assisted arc ignition experiments and the metal inert gas(MIG) arc ignition experiments.This research is helpful to further understanding on the generation mechanism of welding arc ignition and also has a certain academic and practical significance on enriching the welding physical theoretical foundation and improving the precise monitoring on automatic arc welding process.
文摘Horticultural crops with the similar weight and uniform shape are in high demand in terms of marketing value that used as food. The knowledge on existing relationship among the mass, length, width, thickness, volume and projected areas of fruits is useful for proper design of grading machines. A part of this research was aimed to present some physical properties of cherry fruit. In addition, in this study the mass of cherry fruit was predicted with using different physical characteristics in four models including: Linear, Quadratic, S-curve, and Power. According to the results, all properties considered in the current study were found to be statistically significant at the 1% probability level. The best and the worst models for mass prediction of cherry fruit were based on geometric mean diameter and thickness of the cherry with determination coefficients (R2) of 0.938 and 0.484, respectively. At last, mass model of cherry fruit based on first projected area from economical standpoint is recommended.
基金supported by the National Natural Science Foundation of China ( grant no 41327003,41475020 and 41505135)
文摘In order to diminish the effect of the ambient light and CCD pixel non-uniformity to the Precipitation Micro-physical Characteristics Sensor,a modified calibration scheme was designed and calibration experiments in sunny,cloudy,night,different location of sample space were carried out. Firstly,the characteristics of particle images which affected by ambient light and different location of sample space were analyzed. Secondly,the relevance betw een particle image features and parameters of image processing were discussed. Finally,the parameter setting scheme were determined,the radium of median filtering algorithm is 3 pixels,the defocusing radius of point spread function( PSF) is 7 pixels,the radium of erosion is 3 pixels,and the binary threshold is obtained from the Area-thresh relationship. The results show that the new scheme could deal with the image calibration well,the average errors of equivolumetric diameter was 0. 041 mm with standard deviation of 0. 115 mm,and the average errors of the axis ratio was 0. 011 with standard deviation of 0. 085. The new scheme works well in the field observation too,the observed axis ratio is consistent with the empirical relationship that proposed by Beard. The relative error of accumulation precipitation is-3. 06% after calibration,w hich is improved 1. 94% low er than the initial one without calibration.
文摘Tomato (Lycopersicon esculentum Mill) is quantitatively the highest vegetable consumed in Burkina Faso. The objective of this study was to evaluate the physico-chemical, nutritional characteristics, and sanitary quality of the tomato variety Mongal F1 from different production sites. Twenty-eight (28) samples of Mongal F1 fresh tomatoes were collected from 28 producers at three different localities of Ouahigouya, Loumbila and Ouagadougou. The physico-chemical and nutritional characteristics were determined by standardized methods and the traces metallic elements by atomic absorption spectrophotometry. The results revealed a degree brix varying from 4.07° to 5.50° and a pH ranging from 3.71 to 4.08 corresponding to a total acidity of 0.39% to 0.55% citric acid equivalents. The moisture content, the ash content, the total carbohydrates content, the reducing carbohydrates content, the lipids content and the protein content were ranged from 95.09% to 96.17%, 9.25% to 10.60%, 47.00% to 53.43%, 30.03% to 41.21%, 3.04% to 7.71% and 17.09% to 25.03% respectively. The results of the trace metals showed a high accumulation of total cadmium from 0.11 to 0.22 ppm, of total lead of 1.15 to 1.27 ppm and arsenic total of 0.19 to 0.20 ppm. The results proved that environmental conditions influence the quality of the tomato Mongal F1. Detection of trace elements in the tomato fruits suggests that a better production practices are needed.
文摘The physiological properties of new compact vertical-leaf type varieties,such as corn Zhengdan 958,Xundan 18,Jidan 7,etc.were analyzed in order to provid references for its large extension and new high-yield breeding.Results showed that reasons of high-yield included reasonable indices of leaf-area changing,long keeping of corn leaves and slow aging.Photosynthetic pigment,protein and soluble sugar in varietal leaves were high with the high peroxide enzyme activation,photosynthesis inherent ability and photosynthesis eff iciency,but with low malondialdehyde.The volume of grain seed was big,with long forming or starch grouting time of cells and the weight of thousand-granules was high.It indicated that Zhengdan 958 was still the best corn variety for the extensive utilization.The seeds production should pay attention to keep the pure degree and the hallmark for giving full potential advantages on the yield of these species.
基金The National Basic Research Program of China (973 Program) under contract No.2012CB417305COMRA Major Project under contract No.DY125-11-R-01-05the National Natural Science Foundation of China under contract Nos 49906004 and 41104073
文摘Study of petrophysical properties of rocks in seafloor hydrothermal fields has great significance for investigation of seafloor hydrothermal activities,especially for polymetallic sulfides prospecting.In the present study,based on the current experimental conditions,we conducted systematic experiments to measure the magnetic susceptibility,electrical resistivity,porosity,density,as well as acoustic wave velocity of seafloor rocks and sulfides.Subsequently,we measured the physical characteristics of hydrothermal sulfides,basalts and peridotites which were collected from newly discovered seafloor hydrothermal fields at 49.6°E,50.5°E,51°E,63.5°E,and 63.9°E of the Southwest Indian Ridge(SWIR).Previously available and newly collected data were combined to characterize the physical differences between polymetallic sulfides and rocks.We also discussed the impact of hydrothermal alteration on the bedrock and demonstrated how these petrophysical properties of rocks can help in geophysical prospecting of seafloor hydrothermal fields as indicators.
文摘Using standard and internationally validated methods,68 anthropologic characteristics were determined in 314 male(149 from Morin Dawa Daur Autonomous Banner and 165 from Tacheng)and 314 female(158 from Morin Dawa Daur Autonomous Banner,156 from Tacheng)Chinese Daur adults living in Inner Mongolia Autonomous Region and Xinjiang Uygur Autonomous Region.The data were used to calculate 10 anthropologic indices,which were analyzed statistically.The physical characteristics of Daur subjects were analyzed and compared with reference ethnic data.There were some main findings of this study.
文摘Flooding is becoming a yearly reoccurring event in many communities and cities in Nigeria, leading to the destruction of properties and deaths;hence, we must take measures to either prepare for the impact or curb the occurrence. The study identified flood vulnerability levels of communities in Isoko North LGA based on physical environmental domains such as land use, elevation, and proximity to river channel (drainage) using geospatial techniques. Also, attributes that could contribute to the resilience capacity building of the communities were assessed. From the study, 73.93% of the entire area is moderately and highly vulnerable to flood, while among the communities, seventeen (17) are categorized as moderately vulnerable, and four (4) are lowly vulnerable. The overall resilience capacity of the communities indicated can build a substantial capacity towards community resilience (3.02, 0.06). However, there is a need to encourage collaboration with stakeholders to improve mitigation action and enhance various shortcomings toward resilience capacity building.
文摘Sustainable and appropriate watershed management strategies require the determination of biophysical information which includes the floral characteristics of the watershed. This study was conducted to characterize the floral composition of the Bugang River watershed. Data gathering was done by conducting an inventory for trees, palms, and bamboos with Quadrant Sampling using a stratified random sampling method in the forested area of the watershed with 50 m × 20 m sampling plots. Floral species were identified and classified through local experts, published books, journals, the internet, and available references. A total of 60 species belonging to 31 families and 52 genera were found using this method. Gogo (Entada phaseoloides) had the highest number of species with 222 or 14% of the total species. Trees with dbh 10 cm and above have a total estimated volume of 102.31 m<sup>3</sup>. The average diameter and average height of species decrease as the elevation increases. The result showed that the Bugang River watershed has a diverse floral composition, with vertical stratification and a dense canopy. The advocacy and awareness campaign should be done and strengthen the protection and conservation efforts of concerned agencies for the sustainability of the watershed.
文摘This work evaluates some physical parameters (the weight, length, diameter of fruits and seeds, number of seeds per fruit) and the effect of boiling and fermentation on the nutritional value of <em>Telfairia occidentalis </em>(fluted pumpkin) seeds. Firstly, a survey was done in the city of Yaounde on the different treatments applied to the seeds before cooking. From the results of the survey, the seeds were divided into three groups: raw, boiled and fermented. The moisture, lipid, protein, fibre, carbohydrate and ash contents were analysed using AOAC methods and minerals by atomic absorption spectrophotometry. The results showed that <em>T. occidentalis</em> fruit averagely weighed 6.35 kg and contained about 90 seeds. The decorticated seeds had an ovoid shape, 3.70 cm long and weighed 8.91 g. Boiling led to an increase in lipid (16.29% - 31.44%) and carbohydrate (19.20% - 21.8%) but a decrease in protein (54.06% - 34.17%) contents. Fermentation increased the crude fibre (0.70% - 1.1%) but decreased the ash content (4.07% - 3.14% DM). Boiled seeds had higher calcium, magnesium, potassium and sodium, while fermented seeds had higher zinc levels. Boiling proved better in preserving most of the seed nutrients. These seeds could be used to prevent some mineral deficiencies and their high proteins suggest their potential for the formulation of infant foods.
文摘The experiment compared the physical characteristics of aqua feed with crude or gelatinized tapioca starch as sources of energy.The bulk density(BD),water absorption index(WAI),water solubility index(WSI),pellet durability index(PDI)and water stability(WS)were measured in both experimental diets.The results showed significant variations(p<0.05)in BD and WAI in diet with crude tapioca starch while non-significant variations(p>0.05)were recorded for WSI and WS in both diets.The higher BD of a diet,the better its ability in resisting external forces that can cause disintegration.A high BD also reduces ability to the feed material shrinking,thereby preventing loss to feed dust and fines.The results of WSI,WS and PDI of diets denotes that both pellets were water stable and could spend about same time in water but diet with gelatinized starch had a better water absorption index and pellet durability index.Furthermore,proximate composition of diets showed that diets with gelatinized starch had low moisture(9.04%),low fibre(5.24%),and higher ash(13.61%)and lipid(9.64%)contents.It can be concluded from this experiment that diets with gelatinized starch stands the chance of being a better functional feed for small-scale fish farmers in Sub-Saharan Africa.
