precipitation

摘要： First,strip cast samples of high strength microalloyed steel with sub-rapid solidification characteristics were prepared by simulated strip casting technique.Next,the isothermal growth of austenite grain during the reheating treatment of strip casts was observed in situ through confocal laser scanning microscope(CLSM).The results indicated that the time exponent of grains growth suddenly rise when the isothermal temperature higher than 1000°C.And the activation energy for austenite grain growth were calculated to be 538.0 kJ/mol in the high temperature region(above 1000°C)and 693.2 kJ/mol in the low temperature region(below 1000°C),respectively.Then,the kinetics model of austenite isothermal growth was established,which can predict the austenite grain size during isothermal hold very well.Besides,high density of second phase particles with small size was found during the isothermal hold at the low temperature region,leading to the refinement of austenite grain.After isothermal hold at different temperature for 1800 s,the bainite transformation in microalloyed steel strip was also observed in situ during the continuous cooling process.And growth rates of bainite plates with different nucleation positions and different prior austenite grain size(PAGS)were calculated.It was indicated that the growth rate of the bainite plate is not only related to the nucleation position but also to the PAGS.

摘要： In work features of a hydrological regime of catchments of the river of the Pripyat in climate change are considered.Researches of meteorological characteristics of the given territory show the tendency to growth,both tem­peratures of air,and precipitation,evaporation from a surface of water and ground also show the tendency to increase.That is not unequivocally re­flected in change of a course of hydrological characteristics waters objects of territory.On a part of pools of the rivers the mid-annual runoff of water in the rivers in time tends to growth,and Change of levels of subsoil waters decreases for parts-on a turn-here,as a rule,tends a course in time oppo­site to a mid-annual runoff of water in the rivers.Change of the maximal temperature of water in the rivers in time repeats the tendency of a course of a runoff of water in them,i.e.at increase in a runoff of water in the riv­ers-the maximal temperature increases,and at reduction-decreases.The increase in temperature of a superficial component of a runoff of the rivers occurs because of the general increase in temperature of air in considered territory.Silt charge waters in all territory decreases,despite of increase in quantity of atmospheric precipitation and increases or reduction of a runoff of water in the rivers.The relationship between the water runoff layer and precipitation and soil moisture has a certain time delay.The average annual water temperature over time shows a tendency to increase at almost all stations,while the change in the maximum water temperature in rivers over time has a multidirectional tendency and to a greater extent depends on the change in water depth in the river,a decrease in high water maximums and frequent thaws,etc.The studies carried out show that the preservation of moisture in thick layers of soil(0 cm-100 cm)contributes to an increase in water flow in rivers and in the modern conditions of Polesie of Ukraine this will solve a number of problems with the provision of high-quality water resources for various industries and the population.

摘要： The responses of Hongyang,Donghong and Jinhong varieties to temperature and precipitation were analyzed by observing the growth stages of different kiwifruit varieties in Longhe red cartridge kiwifruit base of Liuzhi Special Zone of Guizhou Province in 2021 and combining with the meteorological data of temperature and precipitation in the base in the same period.The results showed that Hongyang,Donghong and Jinhong all sprouted on February 1,and had the same response to temperature and precipitation.From germination to leaf spreading stage,Hongyang and Donghong had the same response to precipitation,while Donghong and Jinhong had the same response to temperature,but Jinhong needed 32.5 mm precipitation to meet its growth and development.From leaf spreading stage to budding stage,Hongyang and Donghong had similar responses to temperature and precipitation,while Jinhong needed average daily temperature of 16.5°Cand precipitation of 2.1 mm.The responses of the three varieties from budding to flowering to temperature and precipitation were consistent.From flowering to fruiting,Hongyang needed 19.9°Ctemperature and the least precipitation,while Jinhong needed the lowest temperature and the maximum precipitation.Donghong's response to temperature and precipitation was between Hongyang and Jinhong.During the period from fruit setting to fruit ripening and picking,Hongyang needed the least temperature and precipitation,while Donghong and Jinhong had the same response to temperature and precipitation.In the key period of fruit expansion of the three kiwifruit varieties in 2021,temperature and precipitation were the most suitable for fruit expansion.In short,red cartridge kiwifruit has a good response to temperature and precipitation in different growth stages,and it requires 201 d for Hongyang variety from germination to maturity and picking,211 d for Donghong variety and 218 d for Jinhong variety.

摘要： This paper evaluates the causal effect of air pollution on the share of domestic value-added in exports for Chinese exporters.Precipitation is employed as an instrument for air pollution to alleviate the endogeneity.Our baseline instrument variable estimation identifies a significant and negative effect of air pollution on the share of domestic value added in exports.Specifically,each 1 mg/m^(3) increase in yearly PM_(2.5) exposure is associated with 3.1447 units decrease of the domestic value-added rate of firms’exports.This result holds when wind speed,air flow index and thermal inversions are used as alternative instruments.Further,it is shown that air pollution is detrimental to the health of employees,and also has negative effect on firms’productivity as well as firms’innovation capacity.All of these may have a negative effect on domestic production and therefore reduce the share of value added done domestically.Lastly,greater effect is found for the central region,the east of Hu Huanyong line,cities of low altitude and high pressure,and also for foreign-invested firms.This paper provides empirical evidence that air pollution may affect the organization of global production,i.e.,the share of domestic value added in Chinese exports,and it certainly contributes to more comprehensive understanding of the effect of air pollution.

摘要： The spatiotemporal variations of water vapor budget(Bt)and their relationships with local precipitation over the Tibetan Plateau(TP)are critical for understanding the characteristics of spatial distributions and evolutions of water resources over the TP.Based on a boundary of the TP,this paper explored the spatiotemporal characteristics of Bt over the TP using the European Centre for Medium-Range Weather Forecasts interim(ERA-Interim)reanalysis datasets.On the climatological mean,the TP is a water vapor sink throughout four seasons and the seasonal variation of Bt is closely associated with the water vapor budget at the southern boundary of the TP.The transient water vapor transport is quasimeridional in the mid-and high-latitude areas and plays a leading role in winter Bt but contributes little in other seasons.At the interannual timescale,the variation of Bt is mainly determined by anomalous water vapor transports at the western and southern boundaries.The Bay of Bengal,the North Arabian Sea,and mid-latitude West Asia are the main sources of excessive water vapor for a wetter TP.At the southern and western boundaries,the transient water vapor budget regulates one-third to four-fifths of Bt anomalies.Moreover,the variability of the TP Bt is closely associated with precipitation over the central-southern and southeastern parts of the TP in summer and winter,which is attributed to the combined effect of the stationary and transient water vapor budgets.Given the role of the transient water vapor transport,the linkage between the TP Bt and local precipitation is tighter.

摘要： Neodymium-iron-boron alloy(Nd2Fe14B)is used in the manufacture of magnets.Neodymium is one of the rare earth elements and is therefore valuable.Recovery,reuse,and recycling of rare earth elements is necessary to protect this rare earth resource.Recently,a new method for recovering neodymium phosphate from iron-neodymium mixture solutions using a two-step precipitation method has been reported,avoiding the difficulties reported with previous methods.In this method,iron compounds were removed in Step I and neodymium phosphate was precipitated in Step II.This novel phosphate process was proposed because rare earth phosphate is the main component of rare earth ores.In this study,we dissolved actual waste magnets in various acids to obtain neodymium phosphate by this two-step precipitation process.The resulting precipitates were evaluated by XRD(X-ray diffraction),infrared spectroscopy,color hue,UV-visible reflectance spectra,Fe/Nd ratio,and recovery of neodymium and iron.The results showed that neodymium phosphate was selectively obtained by using nitric acid and hydrochloric acid.In particular,samples prepared with nitric acid showed no reddening due to iron compounds.

摘要： Precipitation was carried out to obtain manganese carbonate by adding a precipitating agent, sodium carbonate (NaCO3). This was followed by calcination of the manganese carbonate (MnCO3) to obtain manganese dioxide (MnO2). For precipitation tests, a pH ranging from 8 to 10, a time of one to two hours, and a temperature of 25°C and 50°C are the parameters that are considered. The calcination of MnCO3 is carried out under the following conditions: time (1, 2, 3, and 4 hours) and temperature (370°C, 420°C, and 470°C). It should be noted that the temperature range selected for the calcination tests is based on thermodynamic data obtained using the HSC CHEMISTRY software. The results obtained show an effective recovery of manganese at 25°C, in one hour, with a pH of 8.5 with a precipitation yield and manganese content in the precipitate around 98.43% and 24.21%, respectively. During calcination tests, results show an increase in mass loss, for a constant calcination time, as temperature increases. On the other hand, increasing the calcination time at a given temperature causes an increase in mass loss. However, a significant decrease in mass loss is noted at 3 hours of calcination. The highest mass loss is obtained at a temperature of 470°C after 4 hours of calcination.

摘要： Carbon neutrality of the steel industry requires the development of high-strength steel.The mechanical properties of low-alloy steel can be considerably improved at a low cost by adding a small amount of titanium(Ti)element,namely Ti microalloying,whose performance is related to Ti-contained second phase particles including inclusions and precipitates.By proper controlling the precipitation behaviors of these particles during different stages of steel manufacture,fine-grained microstructure and strong precipitation strengthening effects can be obtained in low-alloy steel.Thus,Ti microalloying can be widely applied to produce high strength steel,which can replace low strength steels heavily used in various areas currently.This article reviews the characteristics of the chemical and physical metallurgies of Ti microalloying and the effects of Ti microalloying on the phase formation,microstructural evolution,precipitation behavior of low-carbon steel during the steel making process,especially the thin slab casting and continuous rolling process and the mechanical properties of final steel products.Future development of Ti microalloying is also proposed to further promote the application of Ti microalloying technology in steel to meet the requirement of low-carbon economy.

摘要： Background:The recent rise in temperature and shifting precipitation regimes threaten ecosystems around the globe to different degrees.Treelines are expected to respond to climate warming by shifting to higher elevations,but it is unclear whether they can track temperature changes.Here,we integrated high-resolution aerial imagery with local climatic and topographic characteristics to study the treeline dynamic from 1945 to 2015 on the semiarid Mediterranean island of Crete,Greece.Results:During the study period,the mean annual temperature at the treeline increased by 0.81°C,while the average precipitation decreased by 170 mm.The treeline is characterized by a diffuse form,with trees growing on steep limestone slopes(>50°)and shallow soils.Moreover,the treeline elevation decreases with increasing distance from the coast and with aspect(south>north).Yet,we found no shift in the treeline over the past 70 years,despite an increase in temperature in all four study sites.However,the treeline elevation correlated strongly with topographic exposure to wind(R^(2)=0.74,p<0.001).Therefore,the temporal lag in treeline response to warming could be explained by a combination of topographic and microclimatic factors,such as the absence of a shelter effect and a decrease in moisture.Conclusion:Although there was no treeline shift over the last 70 years,climate change has already started shifting the treeline altitudinal optimum.Consequently,the lack of climate-mediated migration at the treeline should raise concerns about the threats posed by warming,such as drought damages,and wildfire,especially in the Mediterranean region.Therefore,conservation management should discuss options and needs to support adaptive management.

摘要： Understanding the spatio-temporal variations of temperature and precipitation in the arid and semiarid region of China(ASRC)is of great significance for promoting regional eco-environmental protection and policy-making.In this study,the annual and seasonal spatio-temporal patterns of change in average temperature and precipitation and their influencing factors in the ASRC were analyzed using the Mann-Kendall test,linear tendency estimation,accumulative anomaly and the Pearson’s correlation coefficient.The results showed that both annual average temperature and average annual precipitation increased in the ASRC during 1951–2019.The temperature rose by about 1.93°Cand precipitation increased by about 24 mm.The seasonal average temperature presented a significant increase trend,and the seasonal precipitation was conspicuous ascension in spring and winter.The spatio-temporal patterns of change in temperature and precipitation differed,with the southwest area showing the most obvious variation in each season.Abrupt changes in annual and seasonal average temperature and precipitation occurred mainly around the 1990 s and after 2000,respectively.Atmospheric circulation had an important effect on the trends and abrupt changes in temperature and precipitation.The East Asian summer monsoon had the largest impact on the trend of average annual temperature,as well as on the abrupt changes of annual average temperature and precipitation.Temperature and precipitation changes in the ASRC were influenced by long-term and short-term as well as direct and indirect anthropogenic and natural factors.This study identifies the characteristics of spatio-temporal variations in temperature and precipitation in the ASRC and provides a scientific reference for the formulation of climate change responses.