In order to recover the nutrient resource from restaurant garbage, a complete trial with 2 factors on 5 levels of experiments was carried out. The temperature and heating time are the main factors influencing on hydro...In order to recover the nutrient resource from restaurant garbage, a complete trial with 2 factors on 5 levels of experiments was carried out. The temperature and heating time are the main factors influencing on hydrothermal process （HP） by which improves the degradability and digestibility of the restaurant garbage favorably to make animal feeds or fertilizer. The results showed the variation of protein, saccharide, and oil in the garbage. It showed that protein dissolved and liquefied during hydrothermal process, which made organic nitrogen in solid phase transfer to liquid phase. After heating at 180℃ for 60min, organic nitrogen in liquid phase began to transform into ammonia. It also showed that hydrothermal process could promote the dextrinization, dissolution of the starch and its hydrolysis to reducing sugar, due to that starch in the restaurant garbage decreases and reducing sugar increases. When the temperature reached 140℃, the reducing sugar started to decrease due to chemical reactions. The cellulose was stable at 100-180℃. The floatable oil increased markedly in the hydrothermal process. The suitable condition for de-oil was observed at 160℃ heating for 80 min. Furthermore, the extraction of grease from the solid phase accords with first-order reaction dynamic model.展开更多
Formation of super-hydrophobic and corrosion-resistant coatings can provide significant corrosion protection to magnesium alloys.However,it remains a grand challenge to produce such coatings for magnesium-lithium allo...Formation of super-hydrophobic and corrosion-resistant coatings can provide significant corrosion protection to magnesium alloys.However,it remains a grand challenge to produce such coatings for magnesium-lithium alloys due to their high chemical reactivity.Herein,a one-step hydrothermal processing was developed using a stearic-acid-based precursor medium,which enables the hydrothermal conversion and the formation of low surface energy materials concurrently to produce the super-hydrophobic and corrosion-resistant coating.The multiscale microstructures with nanoscale stacks and microscale spheres on the surface,as well as the through-thickness stearates,lead to the super-hydrophobicity and excellent corrosion resistance of the obtained coating.展开更多
To reveal the influencing factors and changing rules for the hydrothermal interaction process of highway subgrade, the field measurements of Shiwei-Labudalin Highway in Inner Mongolia, China was conducted for 3 years,...To reveal the influencing factors and changing rules for the hydrothermal interaction process of highway subgrade, the field measurements of Shiwei-Labudalin Highway in Inner Mongolia, China was conducted for 3 years, based on which the freezing-thawing rules and water content changing characteristics were analyzed. The main results show the subgrade presents a frequent freezing-thawing alternation, and the water content of subgrade exhibits an obvious seasonal alternation. The subbase has the maximum water content, while the base has the minimum water content. The change of water flux is concentrated in the thawing period and consistent with the change of temperature gradient. The subbase layer has the most active water flux due to the heat absorption and impermeability of pavement that easily causes the water accumulation in this layer. Therefore, the prevention and treatment for the freezing-thawing disease should be started from heat insulation and water resistance.展开更多
Well-crystallized hexagonal hematite （α-Fe2O3） platelets were synthesized by hydrothermal process, using a highly concentrated ferric hydroxide as precursor. The precursor was prepared by adding ammonia to the ferr...Well-crystallized hexagonal hematite （α-Fe2O3） platelets were synthesized by hydrothermal process, using a highly concentrated ferric hydroxide as precursor. The precursor was prepared by adding ammonia to the ferric sulfate solution which was obtained by leaching pyrite cinders with sulfuric acid. Structure and morphology of the synthesized products were investigated by X-ray diffraction, scanning electron microscope, transmission electron microscope and selected area electron diffraction. The results reveal that the reaction temperature has significant effects on the structure, size and shape of the synthesized hematite particles. Typical hexagonal hematite platelets, about 0.4-0.6 μm in diameter and 0.1 μm in thickness, were prepared at 230 ℃ for 0.5 h. Al^3＋, contained in the sulfuric acid leaching solution as an impurity, plays an extremely important role in the formation of hexagonal hematite. In addition, a possible mechanism about the formation of hexagonal hematite platelets was proposed.展开更多
The usage of plastic-impregnated waste derived solid fuel in conventional combustor is hindered by many technical factors,especially its organic chlorine content.In this paper,experimental study of hydrothermal treatm...The usage of plastic-impregnated waste derived solid fuel in conventional combustor is hindered by many technical factors,especially its organic chlorine content.In this paper,experimental study of hydrothermal treatment on mixed plastic waste using the mixture of polypropylene,polystyrene,polyethylene and polyvinyl chloride(PVC)has been performed to observe the dechlorination effect of hydrothermal treatment on the waste.The system was generally applying saturated steam at around 2.4 MPa in a stirring reactor for about 90 minutes.After undergoing the process,the organic chlorine in treated plastic waste was reduced to 1,700 ppm level while the inorganic chlorine content was increased,suggesting an organic chlorine conversion phenomenon to inorganic chlorine,accompanied with low pH due to dehydrochlorination process.Additional limestone(Ca(OH)2)in subsequent experiment showed that the similar phenomenon was occurred but with higher pH and lower chlorine content in the condensed water,suggesting the production of inorganic salt rather than hydrochloric acid.Laboratory scale experiment was also performed to confirm the dechlorination phenomena especially for PVC,and the result showed that the main parameter which affected the dechlorination phenomena was the amount of water in hydrothermal process rather than limestone addition.It is suggested that a combination ofhydrothermal process and alkali addition would produce a low-chlorine solid product from plastic waste,promoting its usage as alternative solid fuel.展开更多
ZnO tetrapod-like whiskers were prepared through a hydrothermal process using zinc powder as raw material.Its microstructure and morphology were characterized by X-ray diffraction (XRD) and transmission electron micro...ZnO tetrapod-like whiskers were prepared through a hydrothermal process using zinc powder as raw material.Its microstructure and morphology were characterized by X-ray diffraction (XRD) and transmission electron microscopy (TEM). The XRD results showed that the crystal structure of as-obtained sample can be indexed to hexagonal wurtzite ZnO.TEM results revealed that the ZnO sample took on tetrapod-like whisker shape.The gas sensors were prepared with the traditional sintering process and their gas sensitivities were detected.The test results of gas sensitivity showed that the sensors based on ZnO tetrapod-like whiskers are very sensitive to dilute ethanol vapor and H_2S.The relatively high sensitivity and selectivity of these sensors made from ZnO tetrapod-like whiskers demonstrated the potential for developing a new class of selective ethanol sensors.展开更多
A two-step synthesis was used to control the shape of silver nanoparticles prepared via reduction of Ag^＋ ions in aqueous Ag（NH3）2NO3 by poly（N-vinyl-2 First, a few spherical silver nanoparticles,-10 nm in size, w...A two-step synthesis was used to control the shape of silver nanoparticles prepared via reduction of Ag^＋ ions in aqueous Ag（NH3）2NO3 by poly（N-vinyl-2 First, a few spherical silver nanoparticles,-10 nm in size, were pyrrolidone） （PVP）. Then, in a subsequent hydrothermal treatment, the remaining Ag^＋ ions were reduced by PVP into polyhedral nanoparticles, or larger spherical nanoparticles formed from the small spherical seed silver nanoparticles in the first step. The morphology and size of the resultant particles depend on the hydrothermal temperature, PVP/Ag molar ratio and concentration of Ag^＋ ions. By using UV-visible spectroscopy （UV-vis）, transmission electron microscopy （TEM） and powder X-ray diffraction （XRD）, the possible growth mechanism of the silver nanoparticles was discussed. 2007 Chinese Society of Particuology and Institute of Process Engineering, Chinese Academy of Sciences. Published by Elsevier B.V.展开更多
Hydrothermal processes are key components in permafrost dynamics; these processes are integral to global wanning. In this study the coupled heat and mass transfer model for （CoupModel） the soil-plant-atmosphere-syst...Hydrothermal processes are key components in permafrost dynamics; these processes are integral to global wanning. In this study the coupled heat and mass transfer model for （CoupModel） the soil-plant-atmosphere-system is applied in high-altitude permafrost regions and to model hydrothermal transfer processes in freeze-thaw cycles. Measured meteorological forcing and soil and vegetation properties are used in the CoupModel for the period from January 1, 2009 to December 31, 2012 at the Tanggula observation site in the Qinghai-Tibet Plateau. A 24-h time step is used in the model simulation. The results show that the simulated soil temperature and water content, as well as the frozen depth compare well with the measured data. The coefficient of determination （R2） is 0.97 for the mean soil temperature and 0.73 for the mean soil water content, respectively. The simulated soil heat flux at a depth of 0-20 cm is also consistent with the monitored data. An analysis is performed on the simulated hydrothermal transfer processes from the deep soil layer to the upper one during the freezing and thawing period. At the beginning of the freezing period, the water in the deep soil layer moves upward to the freezing front and releases heat during the freezing process. When the soil layer is completely frozen, there are no vertical water ex- changes between the soil layers, and the heat exchange process is controlled by the vertical soil temperature gradient. During the thaw- ing period, the downward heat process becomes more active due to increased incoming shortwave radiation at the ground surface. The melt water is quickly dissolved in the soil, and the soil water movement only changes in the shallow soil layer. Subsequently, the model was used to provide an evaluation of the potential response of the active layer to different scenarios of initial water content and climate warming at the Tanggula site. The results reveal that the soil water content and the organic layer provide protection against active layer deepening in summer, so climate warming will cause the permafrost active layer to become deeoer and permafrost degradation.展开更多
The mineralization is related closely to sedimentation, diagenesis and hydrothermal processes. In this paper, investigations are carried out on coal occurrence, maceral composition, inorganic minerals, trace elements ...The mineralization is related closely to sedimentation, diagenesis and hydrothermal processes. In this paper, investigations are carried out on coal occurrence, maceral composition, inorganic minerals, trace elements and huminite reflectance. It is concluded that the source of Lincang superlarge deposit is mainly the muscovite granite in the west edge of the basin. During sedimentation, Ge (germanium) was leached out and entered the basin. Ge was adsorbed by lower organism and humic substances in water. Lincang lignite underwent three thermal processes: peatification, early diagenesis and hydrothermal transformation. During peatification, Ge was adsorbed or complexed by humic colloids. During early diagenesis, the Ge associated with humic acids was hard to mobilize or transport. Most of Ge entered the structure of huminite while a small amount of Ge was associated with residual humic acids as complex or humate. During hydrothermal transformation, the heated natural water or deep fluid from basement encountered the coal layer within tectonic weak zone. SO 2- 4 was reduced by coal organic matter. Pyrite and calcite formed. Hydrothermal process did not contribute significantly to mineralization.展开更多
The perovskite-structure CdSnO_(3) was obtained by calcinating CdSnO_(3)·3H_(2)O precursor at 550℃,which was synthesized by hydrothermal process at 170℃for 16 h.The phase and microstructure of the obtained CdSn...The perovskite-structure CdSnO_(3) was obtained by calcinating CdSnO_(3)·3H_(2)O precursor at 550℃,which was synthesized by hydrothermal process at 170℃for 16 h.The phase and microstructure of the obtained CdSnO_(3) powders were characterized by X-ray diffraction(XRD),scanning electron microscopy(SEM)and transmission electron microscopy(TEM).The CdSnO_(3) powders exhibit uniformly cubic structure with side length of about 100 nm.The effects of working temperature and concentration of detected gas on the gas response were studied.The selectivity of chlorine gas against other gases and response-recovery time of the sensor were also investigated.The results reveal that the CdSnO_(3) gas sensor has enhanced sensing properties to 1-10 ppm chlorine gas at room temperature;the value of gas response can reach 1338.9 to 5 ppm chlorine gas.Moreover,the sensor shows good selectivity and quick response behavior(23 s)to chlorine gas,indicating its application in detecting chlorine gas at room temperature in the future.展开更多
The BNT ceramic sample might be a good replacement for PZT piezoelectric in industrial applications,especially in energy harvesting from crystal vibrations.In order to enhance the performance of BNT ceramic,the solid ...The BNT ceramic sample might be a good replacement for PZT piezoelectric in industrial applications,especially in energy harvesting from crystal vibrations.In order to enhance the performance of BNT ceramic,the solid solution was chosen by substitution with Ba+2 at Morphtropic Phase Boundary(MPB).The BNT-xBT powders with x=1,0.07,0.06 and 0 were prepared by the hydrothermal method with average particle size(65–150 nm)at(90℃/72 h).The ceramic disc was sintered at(1150℃/4 h)and showed excellent relative density of about 96%.The results of X-ray diffraction(XRD)confirmed the MPB for x=0:06 and 0.07,while the BNT had a rhombohedral structure and BT had a tetragonal structure.The dielectric measurements showed that BNT,BNT-7BT,BNT-6BT behave as the relaxator ferroelectric and showed a strong dependence on frequency,especially in the MPB region while BT behaves as a normal ferroelectric.Both the Curie temperature and depolarization temperature decrease at the MPB region and showed strong dependency on frequency.展开更多
Millets,nutrient-rich grains packed with complex carbohydrates,dietary fiber,essential proteins,lipids,and antioxidant phytochemicals,are gaining recognition as valuable dietary components.Various processing technique...Millets,nutrient-rich grains packed with complex carbohydrates,dietary fiber,essential proteins,lipids,and antioxidant phytochemicals,are gaining recognition as valuable dietary components.Various processing techniques,including roasting,extrusion,germination,and hydrothermal treatment,have been employed to enhance nutritional bioavailability and consumer appeal.These processing,which involves the application of heat and moisture,induces specific transformations in millet components.Starch undergoes gelatinization,a process in which its crystalline structure is disrupted,leading to increased digestibility and viscosity.Proteins undergo denaturation,altering their structure and potentially improving their digestibility and functionality.Lipids may also undergo modifications,impacting their stability and interactions with other food components.These changes facilitate the release of bioactive compounds such as phenolics,flavonoids,and tannins.These processes effectively reduce anti-nutritional factors,further boosting nutrient availability.This review provides a comprehensive analysis of various hydrothermal methods,including steaming and heat-moisture treatment,and critically evaluates their impact on the physicochemical properties,nutritional profile,and potential health benefits of millet.Steaming,a gentler method involves cooking millet in a steamer basket above boiling water,preserving its delicate texture and nutty flavor while still promoting starch gelatinization and nutrient retention.Heat-moisture treatment,a more specialized technique,involves exposing millet to elevated temperatures and controlled moisture levels,inducing specific changes in starch properties without causing complete gelatinization.This review examines how hydrothermal methods affect the nutritional and functional properties of millet to inspire the development of innovative,nutritious millet-based food products.展开更多
It is known that many kinds of fermentative antibiotics can be removed by temperatureenhanced hydrolysis from production wastewater based on their easy-to-hydrolyze characteristics.However,a few aminoglycosides are ha...It is known that many kinds of fermentative antibiotics can be removed by temperatureenhanced hydrolysis from production wastewater based on their easy-to-hydrolyze characteristics.However,a few aminoglycosides are hard to hydrolyze below 100℃ because of their stability expressed by high molecular energy gap(E).Herein,removal of hard-to-hydrolyze kanamycin residue from production wastewater by hydrothermal treatment at subcritical temperatures was investigated.The results showed the reaction temperature had a significant impact on kanamycin degradation.The degradation half-life(t1/2)was shortened by 87.17-fold when the hydrothermal treatment temperature was increased from 100℃ to 180℃.The t1/2 of kanamycin in the N2 process was extended by 1.08-1.34-fold compared to that of the corresponding air process at reaction temperatures of 140-180℃,indicating that the reactions during hydrothermal treatment process mainly include oxidation and hydrolysis.However,the contribution of hydrolysis was calculated as 75%-98%,which showed hydrolysis played a major role during the process,providing possibilities for the removal of kanamycin from production wastewaters with high-concentration organic matrices.Five transformation products with lower antibacterial activity than kanamycin were identified using UPLC-QTOF-MS analysis.More importantly,hydrothermal treatment could remove 97.9%of antibacterial activity(kanamycin EQ,1,109 mg/L)from actual production wastewater with CODCr around 100,000 mg/L.Furthermore,the methane production yield in anaerobic inhibition tests could be increased about 2.3 times by adopting the hydrothermal pretreatment.Therefore,it is concluded that hydrothermal treatment as a pretreatment technology is an efficient method for removing high-concentration hard-to-hydrolyze antibiotic residues from wastewater with high-concentration organic matrices.展开更多
The resistive switching characteristics of TiO_2 nanowire networks directly grown on Ti foil by a single-step hydrothermal technique are discussed in this paper. The Ti foil serves as the supply of Ti atoms for growth...The resistive switching characteristics of TiO_2 nanowire networks directly grown on Ti foil by a single-step hydrothermal technique are discussed in this paper. The Ti foil serves as the supply of Ti atoms for growth of the TiO_2 nanowires, making the preparation straightforward. It also acts as a bottom electrode for the device. A top Al electrode was fabricated by e-beam evaporation process. The Al/TiO_2 nanowire networks/Ti device fabricated in this way displayed a highly repeatable and electroforming-free bipolar resistive behavior with retention for more than 10~4 s and an OFF/ON ratio of approximately 70. The switching mechanism of this Al/TiO_2 nanowire networks/Ti device is suggested to arise from the migration of oxygen vacancies under applied electric field. This provides a facile way to obtain metal oxide nanowire-based Re RAM device in the future.展开更多
Hydrothermal processing of polyamide 6 （PA6） with the presence of lanthanum chloride （LaC13） was studied in the temperature region from 160 to 250℃. PA6 will be dissolved in the superheated water when temperatur...Hydrothermal processing of polyamide 6 （PA6） with the presence of lanthanum chloride （LaC13） was studied in the temperature region from 160 to 250℃. PA6 will be dissolved in the superheated water when temperature is above 160℃. And as PA6 is dissolved, hydrolysis will happen, which makes PA6 chains degrade. By adding LaCl3 in the hydrothermal environment, the PA6 hydrolysis will intensify, especially when the hydrothermal temperature is higher than 200℃. When the hydrothermal system cools down, the hydrolyzed PA6 segments will crystallize from the solution or remain dissolved in the solution depending on molecular weight. In addition, the hydrolyzed compound of LaCl3 would affect the crystallization of PA6 segments with proper size, and yphase would be presented.展开更多
By orthogonal design theory, technological parameters of chrysanthemum-like ZnO particles prepared in a hydrothermal process are optimized. This paper reports a set of technological parameters for growing chrysanthemu...By orthogonal design theory, technological parameters of chrysanthemum-like ZnO particles prepared in a hydrothermal process are optimized. This paper reports a set of technological parameters for growing chrysanthemumlike ZnO particles on a large scale. It investigates the morphologies and crystalline structures of the as-synthesized three-dimensional ZnO particles with a scanning electron microscope, x-ray diffractometer and transmission electron microscope, and the possible growth mechanism on the three-dimensional ZnO particles. The experimental results indicate that the values of ε′ε″ and tan δe gradually increase in the X band with the improvement of the developmental level of chrysanthemum-like ZnO particles, implying that the electromagnetic wave absorbing property depends on the morphologies of three-dimensional ZnO particles.展开更多
A novel hydrothermal process was developed to extract zinc from pure zinc ferrite（ZnFe2O4） nanopowder and zinc-containing electric arc furnace（EAF） dust using hexahydrated ferric chloride（FeCl3-6H2O） as a decomp...A novel hydrothermal process was developed to extract zinc from pure zinc ferrite（ZnFe2O4） nanopowder and zinc-containing electric arc furnace（EAF） dust using hexahydrated ferric chloride（FeCl3-6H2O） as a decomposing agent.The effects of solid FeCl3-6H2O to ZnFe2O4 ratio by mass（RF/Z）,hydrothermal reaction temperature,and time on zinc extraction were systematically investigated.In the results,when the hydrothermal reaction is conducted at 150℃ for 2 h with RF/Z of 15：20,the efficiency of zinc extraction from ZnFe2O4 reaches97.2%,and the concentration of ferric ions（Fe^3＋） in the leaching solution is nearly zero,indicating a high selectivity for zinc.In addition,the zinc extraction efficiency from the EAF dust reaches 94.5%in the case of the hydrothermal reaction performed at 200℃ for 10 h with the solid FeCl3-6H2O to EAF dust ratio by mass（RF/EAF dust） of 15：10.Zinc and iron separation is achieved by adjusting the pH value of the leaching solution according to the different precipitation pH values of metal hydroxides.展开更多
Ru/CeO_2[RC] and Ru/CeO_2/ethylene glycol（EG） [RCE] nanoparticles were produced by performing a simple hydrothermal reaction at 200℃ for 24 h and found to have two distinct morphologies. The RC nanoparticles are ph...Ru/CeO_2[RC] and Ru/CeO_2/ethylene glycol（EG） [RCE] nanoparticles were produced by performing a simple hydrothermal reaction at 200℃ for 24 h and found to have two distinct morphologies. The RC nanoparticles are phase pureCeO_2; triangular highly crystallineCeCO_3OH nanoparticles are formed from the solution containing EG under the same hydrothermal reaction conditions at p H 8.5. EG plays an important role in the formation of the triangularCeCO_3OH nanoparticles. The polycrystallineCeCO_3OH nanoparticles retain their triangular structure even after calcination at 600℃in air but are transformed into a pureCeO_2 phase. The room temperature photoluminescence of the RC and RCE nanoparticles and of RCE calcined at 600℃[RCE-600] was also investigated. It was found that the high crystallinity triangular RCE-600 sample exhibits the highest photoluminescence intensity.展开更多
The comparison of traditional route to the simple synthesis of CdSe semiconductor nanocrystals, with the hydrothermal route, where the reaction temperature can be reached at 220℃, was presented in this paper. The opt...The comparison of traditional route to the simple synthesis of CdSe semiconductor nanocrystals, with the hydrothermal route, where the reaction temperature can be reached at 220℃, was presented in this paper. The optical properties of the water-soluble CdSe quantum dots from the hydrothermal and traditional were characterized by UV-vis absorption spectra, photoluminescence （PL） spectra and HRTEM techniques. The HRTEM results show that with the increase of the reaction temperature, the naocrystal defects decreased. The UV-vis absorption peak moved to long wave-length with the increase of reaction temperature. The photoluminescence （PL） spectra show that the wavelength of the bright point, the PL quantum yield （QY） increased when the nanocrystal defects decreased. The optical property data confirm that hydrothermal router is a preferable method to traditional route for preparing water-soluble CdSe quantum dots.展开更多
Crystalline cubic cerium oxide nano particles have been synthesized from cerium(Ⅲ)nitrate(Ce(NO_(3))_(3).6H2_(O))and sodium hydroxide by a hydrothermal method.The effect of three different molar ratios of the NaOH pr...Crystalline cubic cerium oxide nano particles have been synthesized from cerium(Ⅲ)nitrate(Ce(NO_(3))_(3).6H2_(O))and sodium hydroxide by a hydrothermal method.The effect of three different molar ratios of the NaOH precipitating agent on structural,optical,and photo catalytic activity was investigated.The synthesized cerium oxide nano particles were characterized by X-ray diffraction(XRD),a UV-vis spectrometer,scanning electron microscope(SEM),energy-dispersive X-ray spectroscopy(EDAX),Raman spectroscopy and X-ray photo electron spectroscopy(XPS).According to the findings,hydrothermally synthesized cerium oxide NPs have a high efficiency for photocatalytic degradation of methylene blue when exposed to UV light.Environmental water pollution is the major issue of the atmosphere.To get fresh water,humans could search the resources to purify the water in simple way and degradation is the one of the methods to purify salt water.展开更多
基金The Cross Project from Beijing Government (No. 2004536)
文摘In order to recover the nutrient resource from restaurant garbage, a complete trial with 2 factors on 5 levels of experiments was carried out. The temperature and heating time are the main factors influencing on hydrothermal process （HP） by which improves the degradability and digestibility of the restaurant garbage favorably to make animal feeds or fertilizer. The results showed the variation of protein, saccharide, and oil in the garbage. It showed that protein dissolved and liquefied during hydrothermal process, which made organic nitrogen in solid phase transfer to liquid phase. After heating at 180℃ for 60min, organic nitrogen in liquid phase began to transform into ammonia. It also showed that hydrothermal process could promote the dextrinization, dissolution of the starch and its hydrolysis to reducing sugar, due to that starch in the restaurant garbage decreases and reducing sugar increases. When the temperature reached 140℃, the reducing sugar started to decrease due to chemical reactions. The cellulose was stable at 100-180℃. The floatable oil increased markedly in the hydrothermal process. The suitable condition for de-oil was observed at 160℃ heating for 80 min. Furthermore, the extraction of grease from the solid phase accords with first-order reaction dynamic model.
基金support from the Fundamental Research Funds for the Central Universities of Hohai university(B200202122)National Natural Science Foundation of China(51878246 and 51979099)+1 种基金the Natural Science Foundation of Jiangsu Province of China(BK20191303)Key Research and Development Project of Jiangsu Province of China(BE2017148).
文摘Formation of super-hydrophobic and corrosion-resistant coatings can provide significant corrosion protection to magnesium alloys.However,it remains a grand challenge to produce such coatings for magnesium-lithium alloys due to their high chemical reactivity.Herein,a one-step hydrothermal processing was developed using a stearic-acid-based precursor medium,which enables the hydrothermal conversion and the formation of low surface energy materials concurrently to produce the super-hydrophobic and corrosion-resistant coating.The multiscale microstructures with nanoscale stacks and microscale spheres on the surface,as well as the through-thickness stearates,lead to the super-hydrophobicity and excellent corrosion resistance of the obtained coating.
基金Project(2018-MSI-018) supported by the Key Science and Technology Project of the Ministry of Transport of ChinaProject(NJ-2018-28) supported by the Construction Science and Technology of the Department of Transport of Inner Mongolia Autonomous Region of China+2 种基金Project(2019MS05029) supported by the Natural Science Fund Project of Inner Mongolia Autonomous Region of ChinaProject(2020MS05077) supported by the Natural Science Fund Project of Inner Mongolia Autonomous Region of ChinaProject(NJ-2020-05) supported by the Research on Complete Survey Technology of Highway Road Area in High-latitude Permafrost Region, China。
文摘To reveal the influencing factors and changing rules for the hydrothermal interaction process of highway subgrade, the field measurements of Shiwei-Labudalin Highway in Inner Mongolia, China was conducted for 3 years, based on which the freezing-thawing rules and water content changing characteristics were analyzed. The main results show the subgrade presents a frequent freezing-thawing alternation, and the water content of subgrade exhibits an obvious seasonal alternation. The subbase has the maximum water content, while the base has the minimum water content. The change of water flux is concentrated in the thawing period and consistent with the change of temperature gradient. The subbase layer has the most active water flux due to the heat absorption and impermeability of pavement that easily causes the water accumulation in this layer. Therefore, the prevention and treatment for the freezing-thawing disease should be started from heat insulation and water resistance.
基金Project(2008A090300016) supported by the Key Science and Technology Item of Guangdong Province,ChinaProject(ZKJ2010022) supported by the Precious Apparatus Opening Center Foundation of Central South University,China
文摘Well-crystallized hexagonal hematite （α-Fe2O3） platelets were synthesized by hydrothermal process, using a highly concentrated ferric hydroxide as precursor. The precursor was prepared by adding ammonia to the ferric sulfate solution which was obtained by leaching pyrite cinders with sulfuric acid. Structure and morphology of the synthesized products were investigated by X-ray diffraction, scanning electron microscope, transmission electron microscope and selected area electron diffraction. The results reveal that the reaction temperature has significant effects on the structure, size and shape of the synthesized hematite particles. Typical hexagonal hematite platelets, about 0.4-0.6 μm in diameter and 0.1 μm in thickness, were prepared at 230 ℃ for 0.5 h. Al^3＋, contained in the sulfuric acid leaching solution as an impurity, plays an extremely important role in the formation of hexagonal hematite. In addition, a possible mechanism about the formation of hexagonal hematite platelets was proposed.
文摘The usage of plastic-impregnated waste derived solid fuel in conventional combustor is hindered by many technical factors,especially its organic chlorine content.In this paper,experimental study of hydrothermal treatment on mixed plastic waste using the mixture of polypropylene,polystyrene,polyethylene and polyvinyl chloride(PVC)has been performed to observe the dechlorination effect of hydrothermal treatment on the waste.The system was generally applying saturated steam at around 2.4 MPa in a stirring reactor for about 90 minutes.After undergoing the process,the organic chlorine in treated plastic waste was reduced to 1,700 ppm level while the inorganic chlorine content was increased,suggesting an organic chlorine conversion phenomenon to inorganic chlorine,accompanied with low pH due to dehydrochlorination process.Additional limestone(Ca(OH)2)in subsequent experiment showed that the similar phenomenon was occurred but with higher pH and lower chlorine content in the condensed water,suggesting the production of inorganic salt rather than hydrochloric acid.Laboratory scale experiment was also performed to confirm the dechlorination phenomena especially for PVC,and the result showed that the main parameter which affected the dechlorination phenomena was the amount of water in hydrothermal process rather than limestone addition.It is suggested that a combination ofhydrothermal process and alkali addition would produce a low-chlorine solid product from plastic waste,promoting its usage as alternative solid fuel.
文摘ZnO tetrapod-like whiskers were prepared through a hydrothermal process using zinc powder as raw material.Its microstructure and morphology were characterized by X-ray diffraction (XRD) and transmission electron microscopy (TEM). The XRD results showed that the crystal structure of as-obtained sample can be indexed to hexagonal wurtzite ZnO.TEM results revealed that the ZnO sample took on tetrapod-like whisker shape.The gas sensors were prepared with the traditional sintering process and their gas sensitivities were detected.The test results of gas sensitivity showed that the sensors based on ZnO tetrapod-like whiskers are very sensitive to dilute ethanol vapor and H_2S.The relatively high sensitivity and selectivity of these sensors made from ZnO tetrapod-like whiskers demonstrated the potential for developing a new class of selective ethanol sensors.
基金This work was supported by the National Natural Science Foundation of China （Grant No. 200573128）the Natural Science Foundation of Shanxi Province, China （Grant No. 20051025）the Natural Science Foundation for Young Scientists of Shanxi Province, China （Grant No. 2006021031）.
文摘A two-step synthesis was used to control the shape of silver nanoparticles prepared via reduction of Ag^＋ ions in aqueous Ag（NH3）2NO3 by poly（N-vinyl-2 First, a few spherical silver nanoparticles,-10 nm in size, were pyrrolidone） （PVP）. Then, in a subsequent hydrothermal treatment, the remaining Ag^＋ ions were reduced by PVP into polyhedral nanoparticles, or larger spherical nanoparticles formed from the small spherical seed silver nanoparticles in the first step. The morphology and size of the resultant particles depend on the hydrothermal temperature, PVP/Ag molar ratio and concentration of Ag^＋ ions. By using UV-visible spectroscopy （UV-vis）, transmission electron microscopy （TEM） and powder X-ray diffraction （XRD）, the possible growth mechanism of the silver nanoparticles was discussed. 2007 Chinese Society of Particuology and Institute of Process Engineering, Chinese Academy of Sciences. Published by Elsevier B.V.
基金National Major Scientific Project of China(No.2013CBA01803)Science Fund for Creative Research Groups of National Natural Science Foundation of China(No.41121001)+1 种基金National Natural Science Foundation of China(No.41271081)Foundation of One Hundred Person Project of Chinese Academy of Sciences(No.51Y251571)
文摘Hydrothermal processes are key components in permafrost dynamics; these processes are integral to global wanning. In this study the coupled heat and mass transfer model for （CoupModel） the soil-plant-atmosphere-system is applied in high-altitude permafrost regions and to model hydrothermal transfer processes in freeze-thaw cycles. Measured meteorological forcing and soil and vegetation properties are used in the CoupModel for the period from January 1, 2009 to December 31, 2012 at the Tanggula observation site in the Qinghai-Tibet Plateau. A 24-h time step is used in the model simulation. The results show that the simulated soil temperature and water content, as well as the frozen depth compare well with the measured data. The coefficient of determination （R2） is 0.97 for the mean soil temperature and 0.73 for the mean soil water content, respectively. The simulated soil heat flux at a depth of 0-20 cm is also consistent with the monitored data. An analysis is performed on the simulated hydrothermal transfer processes from the deep soil layer to the upper one during the freezing and thawing period. At the beginning of the freezing period, the water in the deep soil layer moves upward to the freezing front and releases heat during the freezing process. When the soil layer is completely frozen, there are no vertical water ex- changes between the soil layers, and the heat exchange process is controlled by the vertical soil temperature gradient. During the thaw- ing period, the downward heat process becomes more active due to increased incoming shortwave radiation at the ground surface. The melt water is quickly dissolved in the soil, and the soil water movement only changes in the shallow soil layer. Subsequently, the model was used to provide an evaluation of the potential response of the active layer to different scenarios of initial water content and climate warming at the Tanggula site. The results reveal that the soil water content and the organic layer provide protection against active layer deepening in summer, so climate warming will cause the permafrost active layer to become deeoer and permafrost degradation.
文摘The mineralization is related closely to sedimentation, diagenesis and hydrothermal processes. In this paper, investigations are carried out on coal occurrence, maceral composition, inorganic minerals, trace elements and huminite reflectance. It is concluded that the source of Lincang superlarge deposit is mainly the muscovite granite in the west edge of the basin. During sedimentation, Ge (germanium) was leached out and entered the basin. Ge was adsorbed by lower organism and humic substances in water. Lincang lignite underwent three thermal processes: peatification, early diagenesis and hydrothermal transformation. During peatification, Ge was adsorbed or complexed by humic colloids. During early diagenesis, the Ge associated with humic acids was hard to mobilize or transport. Most of Ge entered the structure of huminite while a small amount of Ge was associated with residual humic acids as complex or humate. During hydrothermal transformation, the heated natural water or deep fluid from basement encountered the coal layer within tectonic weak zone. SO 2- 4 was reduced by coal organic matter. Pyrite and calcite formed. Hydrothermal process did not contribute significantly to mineralization.
基金This project is supported by the Natural Science Foundation of Henan Provincial Education Department,China(Grant Nos.2008B43001 and 2010B150017).
文摘The perovskite-structure CdSnO_(3) was obtained by calcinating CdSnO_(3)·3H_(2)O precursor at 550℃,which was synthesized by hydrothermal process at 170℃for 16 h.The phase and microstructure of the obtained CdSnO_(3) powders were characterized by X-ray diffraction(XRD),scanning electron microscopy(SEM)and transmission electron microscopy(TEM).The CdSnO_(3) powders exhibit uniformly cubic structure with side length of about 100 nm.The effects of working temperature and concentration of detected gas on the gas response were studied.The selectivity of chlorine gas against other gases and response-recovery time of the sensor were also investigated.The results reveal that the CdSnO_(3) gas sensor has enhanced sensing properties to 1-10 ppm chlorine gas at room temperature;the value of gas response can reach 1338.9 to 5 ppm chlorine gas.Moreover,the sensor shows good selectivity and quick response behavior(23 s)to chlorine gas,indicating its application in detecting chlorine gas at room temperature in the future.
文摘The BNT ceramic sample might be a good replacement for PZT piezoelectric in industrial applications,especially in energy harvesting from crystal vibrations.In order to enhance the performance of BNT ceramic,the solid solution was chosen by substitution with Ba+2 at Morphtropic Phase Boundary(MPB).The BNT-xBT powders with x=1,0.07,0.06 and 0 were prepared by the hydrothermal method with average particle size(65–150 nm)at(90℃/72 h).The ceramic disc was sintered at(1150℃/4 h)and showed excellent relative density of about 96%.The results of X-ray diffraction(XRD)confirmed the MPB for x=0:06 and 0.07,while the BNT had a rhombohedral structure and BT had a tetragonal structure.The dielectric measurements showed that BNT,BNT-7BT,BNT-6BT behave as the relaxator ferroelectric and showed a strong dependence on frequency,especially in the MPB region while BT behaves as a normal ferroelectric.Both the Curie temperature and depolarization temperature decrease at the MPB region and showed strong dependency on frequency.
基金the Indian Council of Agriculture Research,All India Coordinated Research Project on Postharvest Engineering and Technology(ICAR-AICRP on PHET)Chaudhary Charan Singh Haryana Agricultural University,Hisar,for providing technical and financial support for the research.
文摘Millets,nutrient-rich grains packed with complex carbohydrates,dietary fiber,essential proteins,lipids,and antioxidant phytochemicals,are gaining recognition as valuable dietary components.Various processing techniques,including roasting,extrusion,germination,and hydrothermal treatment,have been employed to enhance nutritional bioavailability and consumer appeal.These processing,which involves the application of heat and moisture,induces specific transformations in millet components.Starch undergoes gelatinization,a process in which its crystalline structure is disrupted,leading to increased digestibility and viscosity.Proteins undergo denaturation,altering their structure and potentially improving their digestibility and functionality.Lipids may also undergo modifications,impacting their stability and interactions with other food components.These changes facilitate the release of bioactive compounds such as phenolics,flavonoids,and tannins.These processes effectively reduce anti-nutritional factors,further boosting nutrient availability.This review provides a comprehensive analysis of various hydrothermal methods,including steaming and heat-moisture treatment,and critically evaluates their impact on the physicochemical properties,nutritional profile,and potential health benefits of millet.Steaming,a gentler method involves cooking millet in a steamer basket above boiling water,preserving its delicate texture and nutty flavor while still promoting starch gelatinization and nutrient retention.Heat-moisture treatment,a more specialized technique,involves exposing millet to elevated temperatures and controlled moisture levels,inducing specific changes in starch properties without causing complete gelatinization.This review examines how hydrothermal methods affect the nutritional and functional properties of millet to inspire the development of innovative,nutritious millet-based food products.
基金supported by the National Natural Science Foundation of China(Nos.21590814 and 81861138051)。
文摘It is known that many kinds of fermentative antibiotics can be removed by temperatureenhanced hydrolysis from production wastewater based on their easy-to-hydrolyze characteristics.However,a few aminoglycosides are hard to hydrolyze below 100℃ because of their stability expressed by high molecular energy gap(E).Herein,removal of hard-to-hydrolyze kanamycin residue from production wastewater by hydrothermal treatment at subcritical temperatures was investigated.The results showed the reaction temperature had a significant impact on kanamycin degradation.The degradation half-life(t1/2)was shortened by 87.17-fold when the hydrothermal treatment temperature was increased from 100℃ to 180℃.The t1/2 of kanamycin in the N2 process was extended by 1.08-1.34-fold compared to that of the corresponding air process at reaction temperatures of 140-180℃,indicating that the reactions during hydrothermal treatment process mainly include oxidation and hydrolysis.However,the contribution of hydrolysis was calculated as 75%-98%,which showed hydrolysis played a major role during the process,providing possibilities for the removal of kanamycin from production wastewaters with high-concentration organic matrices.Five transformation products with lower antibacterial activity than kanamycin were identified using UPLC-QTOF-MS analysis.More importantly,hydrothermal treatment could remove 97.9%of antibacterial activity(kanamycin EQ,1,109 mg/L)from actual production wastewater with CODCr around 100,000 mg/L.Furthermore,the methane production yield in anaerobic inhibition tests could be increased about 2.3 times by adopting the hydrothermal pretreatment.Therefore,it is concluded that hydrothermal treatment as a pretreatment technology is an efficient method for removing high-concentration hard-to-hydrolyze antibiotic residues from wastewater with high-concentration organic matrices.
基金supported by the Natural Sciences and Engineering Research Council(NSERC)of CanadaThe financial support of the State Scholarship Fund of China(No.201506160061)
文摘The resistive switching characteristics of TiO_2 nanowire networks directly grown on Ti foil by a single-step hydrothermal technique are discussed in this paper. The Ti foil serves as the supply of Ti atoms for growth of the TiO_2 nanowires, making the preparation straightforward. It also acts as a bottom electrode for the device. A top Al electrode was fabricated by e-beam evaporation process. The Al/TiO_2 nanowire networks/Ti device fabricated in this way displayed a highly repeatable and electroforming-free bipolar resistive behavior with retention for more than 10~4 s and an OFF/ON ratio of approximately 70. The switching mechanism of this Al/TiO_2 nanowire networks/Ti device is suggested to arise from the migration of oxygen vacancies under applied electric field. This provides a facile way to obtain metal oxide nanowire-based Re RAM device in the future.
基金financially supported by the National Natural Science Foundation of China(No.51373032)Innovation Program of Shanghai Municipal Education Commission+1 种基金Fundamental Research Funds for the Central Universityfinancial support from Chinese Universities Scientific Fund(No.CUSF-DH-D-2014025)
文摘Hydrothermal processing of polyamide 6 （PA6） with the presence of lanthanum chloride （LaC13） was studied in the temperature region from 160 to 250℃. PA6 will be dissolved in the superheated water when temperature is above 160℃. And as PA6 is dissolved, hydrolysis will happen, which makes PA6 chains degrade. By adding LaCl3 in the hydrothermal environment, the PA6 hydrolysis will intensify, especially when the hydrothermal temperature is higher than 200℃. When the hydrothermal system cools down, the hydrolyzed PA6 segments will crystallize from the solution or remain dissolved in the solution depending on molecular weight. In addition, the hydrolyzed compound of LaCl3 would affect the crystallization of PA6 segments with proper size, and yphase would be presented.
基金supported by the National High Technology Research and Development Program of China (Grant No 2005A000200)the Xi’an Applied Materials Innovation Fund (Grant No XA-AM-200712)the Innovative Experiment Program for Chinese students (Grant No State 200721)
文摘By orthogonal design theory, technological parameters of chrysanthemum-like ZnO particles prepared in a hydrothermal process are optimized. This paper reports a set of technological parameters for growing chrysanthemumlike ZnO particles on a large scale. It investigates the morphologies and crystalline structures of the as-synthesized three-dimensional ZnO particles with a scanning electron microscope, x-ray diffractometer and transmission electron microscope, and the possible growth mechanism on the three-dimensional ZnO particles. The experimental results indicate that the values of ε′ε″ and tan δe gradually increase in the X band with the improvement of the developmental level of chrysanthemum-like ZnO particles, implying that the electromagnetic wave absorbing property depends on the morphologies of three-dimensional ZnO particles.
基金supported by the National Basic Research Priorities Program of China (Nos. 2014CB643401 and 2013AA032003)the National Natural Science Foundation of China (No.51372019)
文摘A novel hydrothermal process was developed to extract zinc from pure zinc ferrite（ZnFe2O4） nanopowder and zinc-containing electric arc furnace（EAF） dust using hexahydrated ferric chloride（FeCl3-6H2O） as a decomposing agent.The effects of solid FeCl3-6H2O to ZnFe2O4 ratio by mass（RF/Z）,hydrothermal reaction temperature,and time on zinc extraction were systematically investigated.In the results,when the hydrothermal reaction is conducted at 150℃ for 2 h with RF/Z of 15：20,the efficiency of zinc extraction from ZnFe2O4 reaches97.2%,and the concentration of ferric ions（Fe^3＋） in the leaching solution is nearly zero,indicating a high selectivity for zinc.In addition,the zinc extraction efficiency from the EAF dust reaches 94.5%in the case of the hydrothermal reaction performed at 200℃ for 10 h with the solid FeCl3-6H2O to EAF dust ratio by mass（RF/EAF dust） of 15：10.Zinc and iron separation is achieved by adjusting the pH value of the leaching solution according to the different precipitation pH values of metal hydroxides.
基金support provided by King Abdulaziz City for Science and Technology(KACST)through the Science&Technology Unit at King Fahd University of Petroleum&Minerals(KFUPM)for funding this work through project No.AT-32-21
文摘Ru/CeO_2[RC] and Ru/CeO_2/ethylene glycol（EG） [RCE] nanoparticles were produced by performing a simple hydrothermal reaction at 200℃ for 24 h and found to have two distinct morphologies. The RC nanoparticles are phase pureCeO_2; triangular highly crystallineCeCO_3OH nanoparticles are formed from the solution containing EG under the same hydrothermal reaction conditions at p H 8.5. EG plays an important role in the formation of the triangularCeCO_3OH nanoparticles. The polycrystallineCeCO_3OH nanoparticles retain their triangular structure even after calcination at 600℃in air but are transformed into a pureCeO_2 phase. The room temperature photoluminescence of the RC and RCE nanoparticles and of RCE calcined at 600℃[RCE-600] was also investigated. It was found that the high crystallinity triangular RCE-600 sample exhibits the highest photoluminescence intensity.
基金Founded by the National Natural Science Foundation of China(NSFC) (No.50572072)Science and Technology Commission of Shanghai Municipality (SCTSM)(No.0452nm059)
文摘The comparison of traditional route to the simple synthesis of CdSe semiconductor nanocrystals, with the hydrothermal route, where the reaction temperature can be reached at 220℃, was presented in this paper. The optical properties of the water-soluble CdSe quantum dots from the hydrothermal and traditional were characterized by UV-vis absorption spectra, photoluminescence （PL） spectra and HRTEM techniques. The HRTEM results show that with the increase of the reaction temperature, the naocrystal defects decreased. The UV-vis absorption peak moved to long wave-length with the increase of reaction temperature. The photoluminescence （PL） spectra show that the wavelength of the bright point, the PL quantum yield （QY） increased when the nanocrystal defects decreased. The optical property data confirm that hydrothermal router is a preferable method to traditional route for preparing water-soluble CdSe quantum dots.
文摘Crystalline cubic cerium oxide nano particles have been synthesized from cerium(Ⅲ)nitrate(Ce(NO_(3))_(3).6H2_(O))and sodium hydroxide by a hydrothermal method.The effect of three different molar ratios of the NaOH precipitating agent on structural,optical,and photo catalytic activity was investigated.The synthesized cerium oxide nano particles were characterized by X-ray diffraction(XRD),a UV-vis spectrometer,scanning electron microscope(SEM),energy-dispersive X-ray spectroscopy(EDAX),Raman spectroscopy and X-ray photo electron spectroscopy(XPS).According to the findings,hydrothermally synthesized cerium oxide NPs have a high efficiency for photocatalytic degradation of methylene blue when exposed to UV light.Environmental water pollution is the major issue of the atmosphere.To get fresh water,humans could search the resources to purify the water in simple way and degradation is the one of the methods to purify salt water.
