Given the depletion of high-quality magnesite deposits and the rising demand for high-end magnesium materials,the separation and utilization of high-calcium magnesite ores have become essential.However,the similar sur...Given the depletion of high-quality magnesite deposits and the rising demand for high-end magnesium materials,the separation and utilization of high-calcium magnesite ores have become essential.However,the similar surface properties and solubility of semi-soluble salt-type minerals,pose significant challenges for the utilization of dolomite-rich magnesite resources.In this study,1-hydroxypropane-1,1-di phosphonic acid(HPDP)was identified for the first time as a high-performance depressant for dolomite.Various tests,including contact angle measurements,ζ potential analysis,X-ray photoelectron spectroscopy,and atomic force microscopy,were conducted to elucidate the interfacial interaction mechanisms of HPDP on the surfaces of the two minerals at different scales.Additionally,molecular modeling calculations were used to detail the spatial matching relationship between HPDP and the crystal faces of the two minerals.It was emphasized that HPDP specifically adsorbed onto the dolomite surface by forming calcium phosphonate,ensuring that the dolomite surface remained hydrophilic and sank.Moreover,it was found that the adsorption strength of HPDP on the mineral surfaces depended on the activity of the metal sites and their spatial distribution.These findings provide a theoretical foundation for the molecular design of flotation reagents for high-calcium magnesite ores.展开更多
An accelerated laboratory method（saturated ammonium nitrate solution immersion method） was used to analyze the degradation of cement decalcification process. By studying the changes of intensity, volume, elastic mod...An accelerated laboratory method（saturated ammonium nitrate solution immersion method） was used to analyze the degradation of cement decalcification process. By studying the changes of intensity, volume, elastic modulus, quality, p H value, the Ca/Si, and mineral phase, it could be found that the first cement decalcification degradation process was the decalcification of calcium hydroxide, and then CSH gel, AFm, etc. The secondary ettringite deposition happened and the decalcification degradation depth was proportional to the square root of time. Moreover, the corresponding strength of cement would be gradually reduced, cement rock volume shrinkage occurred, p H values decreased, the surface elastic modulus decreased down to a certain level, and slightly changed and the Ca/Si was 3.1 from the beginning and lasted down to 1.3.展开更多
The freezing acidolysis solution of the nitric acid-phosphate fertilizer process has a high calcium content,which makes it difficult to produce fine phosphate and high water-soluble phosphate fertilizer products.Here,...The freezing acidolysis solution of the nitric acid-phosphate fertilizer process has a high calcium content,which makes it difficult to produce fine phosphate and high water-soluble phosphate fertilizer products.Here,based on the potential crystallization principle of calcium sulfate in NH_(4)NO_(3)-H_(3)PO_(4)-H_(2)O,the deep decalcification(i.e.calcium removal)technology to achieveα-high-strength gypsum originated from freezing acidolysis-solutions has been firstly proposed and investigated.Typically,calcium can be removed from the factory-provided freezing acidolysis-solution by neutralizing it with ammonia,followed by the addition of ammonium sulfate solution.As a result,the formation of calcium sulfate in the reaction system undergoes the nucleation and growth of CaSO_(4)·2H_(2)O(DH),as well as its dissolution and crystallization into short columnarα-CaSO_(4)·0.5H_(2)O(α-HH).Remarkably,with the molar ratio of SO_(4)^(2-)/Ca^(2+)at 1.8,the degree of neutralization(NH_(3)/HNO_(3) molar ratio)at 1.7,the reaction temperature of 94℃,and the reaction time of 300 min,the decalcification rate can reach 86.89%,of which the high-strengthα-CaSO_(4)·0.5H_(2)O(α-HH)will be obtained.Noteworthy,the deep decalcification product meets the standards for the production of fine phosphates and highly water-soluble phosphate fertilizers.Consequently,the 2 h flexural strength ofα-HH is 5.3 MPa and the dry compressive strength is 36.8 MPa,which is up to the standard of commercialα-HH.展开更多
Biological insecticides have gained importance in modern society because they cause minimal environmental harm and reduce pests’ability to develop resistance.Nomuraea rileyi,a facultative entomopathogenic fungus,is s...Biological insecticides have gained importance in modern society because they cause minimal environmental harm and reduce pests’ability to develop resistance.Nomuraea rileyi,a facultative entomopathogenic fungus,is suitable for infecting lepidopteran pests,including Spodoptera litura and Helicoverpa armigera.This work aims to identify a suitable semi-solid fermentation medium to increase the conidia production of N.rileyi and enhance its biological control ability as mycoinsecticide.Research is carried out on broken rice,wheat,sorghum,and corn as substrates,both with and without nutrient addition.It also covers incubation under set conditions,colony harvesting,and conidial yield and germination determination using a haemocytometer.All the study was conducted using a completely randomized design(CRD)and a test of significance was set at p<0.05 using analysis of variance(ANOVA).This work aimed to establish the effect of various substrates on growth and conidia formation in N.rileyi.The highest conidia count of 10×10^(8)CFU/g on day 15.The result was obtained from BR+Nu followed by sorghum 7×10^(8)CFU/g,corn 7×10^(8)CFU/g and wheat 6.5×10^(8)CFU/g.Thus,post-drying,the highest corresponding viability was observed in the product containing BR+Nu–6.20×10^(8)CFU/g.Adding rice bran(BR+RB,150 g each)still increases conidial yield up to 14×10^(8) CFU/g at 15 DAI.These indings thus assert that broken rice and supplementation affect conidia yield and viability.展开更多
BACKGROUND Routine assessment of solid gastric emptying is challenging due to the prolonged test duration and complex meal preparation.Replacing solid test meals with easily prepared,commercially available semisolid m...BACKGROUND Routine assessment of solid gastric emptying is challenging due to the prolonged test duration and complex meal preparation.Replacing solid test meals with easily prepared,commercially available semisolid meals and shortening the test duration can significantly enhance the feasibility and practicality of gastric emptying evaluations.AIM To compare the gastric emptying and antral motility of solid vs semi-solid meals of similar volume and nutritional consistency,and to assess the feasibility of meal substitution and reduction in test duration during the solid gastric emptying assessment.METHODS Thirty healthy volunteers(17 males,age:29.4±6.0 years,body mass index:23.4±2.94 and 13 females,age:37.2±11.9 years,body mass index:22.9±4.34)underwent gastric emptying by real-time ultrasonography after a solid meal and a comparable commercially prepared semi-solid meal(each meal,total calorie 350 kcal,carbohydrates 60%,fat 30%and proteins 10%),on separate dates 1 week apart.The gastric antral area was measured at 5 minutes,15 minutes,30 minutes,45 minutes,60 minutes,90 minutes,120 minutes,150 minutes,180 minutes,210 minutes,and 240 minutes post-ingestion using a previously validated technique and compared between meals.RESULTS Mean and median antral areas,gastric emptying rates,gastric residual ratios,and motility index at each time point were almost similar between meals for up to 3 hours.At the end of 4 hours,the mean emptied percentage of the semisolid meal and solid meal was 81.1%and 70.6%,respectively.The emptying rate of the semisolid meal at 90 minutes significantly correlated with that of 240 minutes.There was no correlation between the solid meal emptying rates at 90 minutes and 240 minutes.CONCLUSION Gastric emptying,residual antral cross-sectional area and antral motility of a semisolid meal are almost similar to that of a solid meal of the same nutritional value until three hours post-ingestion.A semisolid test meal can effectively substitute a solid test meal during ultrasound assessment of gastric emptying,without compromising the validity of the results.Additionally,the ease of preparation and administration of semisolid meals enhances the overall feasibility of gastric emptying assessments.展开更多
Through the innovative integration of semi-solid rheo-casting with extrusion shear process,the short-process fabrication of low-alloyed wrought Mg-2Zn-1Mn alloy is achieved in this study.Uniaxial tensile testing of lo...Through the innovative integration of semi-solid rheo-casting with extrusion shear process,the short-process fabrication of low-alloyed wrought Mg-2Zn-1Mn alloy is achieved in this study.Uniaxial tensile testing of low-temperature extrusion shear specimens(200℃)demonstrates the exceptional strength-ductility synergy,yield strength of 277 MPa,yield strength ratio of 0.95,and elongation of 24%.Microstructural observations reveal the mechanisms underlying its high strength-plasticity synergy at room temperature.This study investigates the effects of different temperature gradients on the microstructure by analyzing experiments conducted at three temperatures:300℃,250℃,and 200◦C.Ultimately,the formation mechanism of the bimodal microstructure obtained at 200℃ is elucidated.The distinctive crystallographic texture oriented at 34°relative to the loading axis direction effectively mitigates stress concentration by inducing the synergistic activation of multiple slip systems.Furthermore,the transition trends of different slip systems and texture evolution during tensile deformation are validated through Visco-Plastic Self-Consistent(VPSC)simulations and corroborated by microstructural analysis.With geometrically necessary dislocation(GND)density(4.28×10^(15)m^(-2))and pyramidal slip activation(~45%).This study has successfully broken through the bottleneck of strength-ductility trade-off in magnesium alloys,providing theoretical support for the development of high-reliability magnesium alloys.展开更多
The Al-Mg_(2)Si in-situ composite is a lightweight material with great potential for application in fields such as automotive lightweighting,aerospace,and electronic components.In this research,the modification,semi-s...The Al-Mg_(2)Si in-situ composite is a lightweight material with great potential for application in fields such as automotive lightweighting,aerospace,and electronic components.In this research,the modification,semi-solid technology coupled with different types of electromagnetic stirring was applied to regulate the undesirable solidified dendritic microstructure and facilitate the composites’mechanical properties.The spheroidization and refinement of Mg_(2)Si andα-Al matrix in SM(semi-solid)+RES(rotate electromagnetic stirring)sample and SM+SHES(single winding helical electromagnetic stirring)sample are realized under the effect of fused dendrite arm,the decreased critical nucleate radius,and the increased nucleation rate and extra supercooling degree induced by electromagnetic stirring.The Mg_(2)Si phase in the SM+RES sample and SM+SHES sample is refined by 73.4%and 75.7%,respectively compared to the AC(as-cast)sample.Besides,the single winding electromagnetic stirring can lead to more homogeneously distributed physical fields,lower temperature gradient,and more significant mass transfer,mainly responsible for the more homogeneous distributed reinforced finer Mg_(2)Si particles in the SM+SHES sample.Moreover,both the tensile properties and hardness of modified semi-solid composites are improved through electromagnetic stirring.Compared with RES,the improvement effect of SHES is more excellent.The SM+SHES sample possesses the highest Brinell hardness(124.7 HB),and its quality index of tensile properties is 5.73%and 82.2%higher than that of the SM+RES and AC samples,respectively.展开更多
Semi-solid squeeze casting（SSSC） and liquid squeeze casting（LSC） processes were used to fabricate a ZL104 connecting rod, and the influences of the process parameters on the microstructures and mechanical properti...Semi-solid squeeze casting（SSSC） and liquid squeeze casting（LSC） processes were used to fabricate a ZL104 connecting rod, and the influences of the process parameters on the microstructures and mechanical properties were investigated. Results showed that the tensile strength and elongation of the SSSC-fabricated rod were improved by 22% and 17%, respectively, compared with those of the LSC-fabricated rod. For SSSC, the average particle size（APS） and the shape factor（SF） increased with the increase of re-melting temperature（Tr）, whereas the tensile strength and elongation increased first and then decreased. The APS increased with increasing the mold temperature（Tm）, whereas the SF increased initially and then decreased, which caused the tensile strength and elongation to increase initially and then decrease. The APS decreased and the SF increased as squeezing pressure（ps） increased, and the mechanical properties were enhanced. Moreover, the optimal Tr, ps and Tm are 848 K, 100 MPa and 523 K, respectively.展开更多
The effects of cooling conditions on the microstructure of semi-solid AZ91 slurry produced via ultrasonic vibration process were investigated. AZ91 melts were subjected to ultrasonic vibration in different temperature...The effects of cooling conditions on the microstructure of semi-solid AZ91 slurry produced via ultrasonic vibration process were investigated. AZ91 melts were subjected to ultrasonic vibration in different temperature ranges under different cooling rates. The results show that fine and spherical α-Mg particles are obtained under ultrasonic vibration at the nucleation stage, which is mainly attributed to the cavitation and acoustic streaming induced by the ultrasonic vibration. The reduction of lower limit of ultrasonic vibration temperature between the liquidus and solidus increases the solid volume fraction and average particle size. Increasing cooling rate increases the solid volume fraction and reduces the average shape factor of particles. The appropriate temperature range for ultrasonic vibration is from 605 °C to 595 °C or 590 °C, and the suitable cooling rate is 2-3 °C/min.展开更多
Microstructure evolution of Ti14 （α＋Ti2Cu） alloy during semi-solid isothermal process at different temperatures was investigated. The results reveal that both the temperature and holding time have effect on the gr...Microstructure evolution of Ti14 （α＋Ti2Cu） alloy during semi-solid isothermal process at different temperatures was investigated. The results reveal that both the temperature and holding time have effect on the grain growth behavior. The grains grow obviously and the degree of globularity increases with the increase of holding time. According to the statistic analysis of experimental data, the grain growth indices are 0.88 and 0.97 at 1 000 ℃ and 1 050 ℃, respectively, which indicates that increasing isothermal temperature would accelerate microstructural evolution.展开更多
The semi-solid slurry of 7075 aluminum alloy was prepared by a serpentine pouring channel （SCP）. Influences of pouring temperature and the number of turns on the microstructure of semi-solid 7075 alloy slurry were i...The semi-solid slurry of 7075 aluminum alloy was prepared by a serpentine pouring channel （SCP）. Influences of pouring temperature and the number of turns on the microstructure of semi-solid 7075 alloy slurry were investigated. The results demonstrated that the semi-solid 7075 aluminum alloy slurry with satisfied quality could be generated by a serpentine pouring channel when the pouring temperature was in the range of 680-700 ℃. At a given pouring temperature, the equivalent size of the primaryα（Al） grains decreased and the shape factor increased with the increase of the number of turns. During the slurry preparation of semi-solid 7075 aluminum alloy, the flow direction of alloy melt changed many times when it flowed in a curved and closed serpentine channel. With the effect of“stirring”in it , the primary nuclei gradually evolved into spherical and near-spherical grains.展开更多
The inhomogeneity of density and mechanical properties of A357 aluminum alloy in the semi-solid state were investigated.Numerical simulation and backward extrusion were adopted to study the preparation of cup shells.T...The inhomogeneity of density and mechanical properties of A357 aluminum alloy in the semi-solid state were investigated.Numerical simulation and backward extrusion were adopted to study the preparation of cup shells.The results show that the relative density of the wall is the lowest in samples,and that of the base is the highest.With increasing the billet height,more time is needed for relative density of the corner to reach the maximum value,and the relative densities in every region improve evidently with increasing the pressure.The tensile stress was simulated to be the largest at the corner,and the hot tearings were forecasted to mainly appear at the corner too.By employing proper billet height and pressure,the extruded samples consisted of fine and uniform microstructures,and can obtain excellent mechanical properties and Brinell hardness.展开更多
Semi-solid 7075 Al slurry was prepared by inverted cone-shaped pouring channel process （ICSPC） and temperature homogenization （TH） treatment was combined to make the slurry uniform and have a controllable solid fr...Semi-solid 7075 Al slurry was prepared by inverted cone-shaped pouring channel process （ICSPC） and temperature homogenization （TH） treatment was combined to make the slurry uniform and have a controllable solid fraction suitable for the follow-up rheocasting. The influence of cooling rate on the microstructure evolution of primary α（Al） during TH treatment was investigated. The results show that as the cooling rate of the slurry after being prepared reduces, the growth of primaryα（Al） in the slurry tends to be nearly spherical and the uniformity of the organization is also enhanced. This may be due to the fact that lower cooling rate plays an important role in achieving the uniformity of temperature and composition in the remaining liquid, which is crucial to the formation of the spherical and homogeneous microstructure. However, a too low cooling rate will lead to a significant increase in grain growth time, which makes too coarse grains and more particles coalesce, so a certain abnormal growth of grain appears and the shape factor decreases slightly.展开更多
The electronic packaging box with high silicon aluminum-base alloy was prepared by semi-solid thixoforming technique.The flow characteristic of the Si phase was analyzed.The microstructures of different parts of the b...The electronic packaging box with high silicon aluminum-base alloy was prepared by semi-solid thixoforming technique.The flow characteristic of the Si phase was analyzed.The microstructures of different parts of the box were observed by optical microscopy and scanning electron microscopy,and the thermophysical and mechanical properties of the box were tested.The results show that there exists the segregation phenomenon between the primary Si phase and the liquid phase during thixoforming,the liquid phase flows from the box,and the primary Si phase accumulates at the bottom of the box.The volume fraction of primary Si phase decreases gradually from the bottom to the walls.Accordingly,the thermal conductivities of bottom center and walls are 107.6 and 131.5 W/（m·K）,the coefficients of thermal expansion（CTE） are 7.9×10-6 and 10.6×10-6 K-1,respectively.The flexural strength increases slightly from 167 to 180 MPa.The microstructures and properties of the box show gradient distribution overall.展开更多
Semi-solid A356 aluminum alloy slurry was prepared by using serpentine channel pouring process, and the influences of the channel diameters and pouring temperatures on the semi-solid A356 aluminum alloy slurry were in...Semi-solid A356 aluminum alloy slurry was prepared by using serpentine channel pouring process, and the influences of the channel diameters and pouring temperatures on the semi-solid A356 aluminum alloy slurry were investigated. The experimental results show that when the channel diameter is 20 and 25 mm, respectively, and the pouring temperature is 640-680 ℃, the average diameter of primary α（Al） grains in the prepared A356 aluminum alloy slurry is 50-75 and 55-78 μm, respectively, and the average shape factor of primary α（Al） grains is 0.89-0.76 and 0.86-0.72, respectively. With the decline in the pouring temperature, the microstructure of semi-solid A356 aluminum alloy slurry is more desirable and a serpentine channel with smaller diameter is also advantageous to the microstructure imProvement. During the preparation of semi-solid A356 aluminum alloy slurry, a large number of nuclei can be produced by the chilling effect of the serpentine channel, and owing to the combined effect of the chilled nuclei separation and melt self-stirring, primary α（Al） nuclei can be multiplied and spheroidized finally.展开更多
The semi-solid slurry of A380 aluminum alloy was prepared by the serpentine channel. The effects of pouring temperature, curve number and curve diameter of the serpentine channel on the microstructure of the semi-soli...The semi-solid slurry of A380 aluminum alloy was prepared by the serpentine channel. The effects of pouring temperature, curve number and curve diameter of the serpentine channel on the microstructure of the semi-solid A380 aluminum alloy slurry were investigated. The results show that the satisfactory semi-solid A380 aluminum alloy slurry could be obtained when the pouring temperature ranged from 630 to 650 °C. Under the same conditions, increasing the curve number or reducing the curve diameter of the serpentine channel would decrease the average diameter and increase the shape factor of the primary α（Al） grains. The ＂self-stirring＂ of the alloy melt in the serpentine channel was beneficial to the ripening of the dendrites and the spheroidizing of the primary α（Al） grains.展开更多
The microstructural evolution of AZ91D magnesium alloy prepared by means of the cyclic upsetting-extrusion and partial remelting was investigated. The effects of remelting temperature and holding time on microstructur...The microstructural evolution of AZ91D magnesium alloy prepared by means of the cyclic upsetting-extrusion and partial remelting was investigated. The effects of remelting temperature and holding time on microstructure of semi-solid AZ91D magnesium alloy were studied. Furthermore, tensile properties of thixoextruded AZ91D magnesium alloy components were determined. The results show that the cyclic upsetting-extrusion followed by partial remelting is effective in producing semi-solid AZ91D magnesium alloy for thixofonning. During the partial remelting, with the increase of remelting temperature and holding time, the solid grain size increases and the degree of spheroidization tends to be improved. The tensile mechanical properties of thixoextruded AZ91D magnesium alloy components produced by cyclic upsetting-extrusion and partial remelting are better than those of the same alloy produced by casting.展开更多
The semi-solid slurry of AZ91 D magnesium alloy was prepared by gas bubbling process.The effect of processing parameters,including gas flow rate,cooling rate and stirring end temperature,on microstructure of AZ91 D se...The semi-solid slurry of AZ91 D magnesium alloy was prepared by gas bubbling process.The effect of processing parameters,including gas flow rate,cooling rate and stirring end temperature,on microstructure of AZ91 D semi-solid slurry was investigated.With increasing the gas flow rate from 0 to 5 L/min,the average size of primary α-Mg particles decreases from 119.1 to77.2μm and the average shape factor increases continuously from 0.1 to 0.596.The formation of non-dendritic primary α-Mg particles during gas bubbling is the result of combined effects of dendrite fragmentation and copious nucleation.With increasing the cooling rate from 3.6 to 14.6℃/min,the average particle size of primary α-Mg phase decreases from 105.0 to 68.1μm while the average shape factor peaks at 9.1℃/min.Both high and low cooling rates can induce dendritic growth of primary α-Mg particles.Changing the stirring end temperature from 590 to 595℃ has little effect on the average size and shape factor of primary α-Mg particles in AZ91 D semi-solid slurry.The insensitivity of semi-solid microstructures to the stirring end temperature is attributed to the sufficient quantity of primary particles formed in the melt.展开更多
In order to study the hot fractures in relation to the semi-solid processing, the tensile tests of an extruded 7075 aluminum alloy which is based on Al?Zn?Mg?Cu system were carried out in the high temperature solid an...In order to study the hot fractures in relation to the semi-solid processing, the tensile tests of an extruded 7075 aluminum alloy which is based on Al?Zn?Mg?Cu system were carried out in the high temperature solid and semi-solid states at different strain rates. The results show that the tensile behavior can be divided into three regimes with increasing the liquid fraction. The alloy first behaves in a ductile character, and as the temperature increases, the fracture mechanism changes from ductile to brittle which is determined by both of liquid and solid, and lastly the fracture mechanism is brittle which is totally dominated by liquid. At strain rates of 1×10?4, 1×10?3 and 1×10?2 s?1, the brittle temperature ranges are 515?526, 519?550 and 540?580 °C, respectively. Two equations which are critical for tensile behavior are proposed.展开更多
基金supported by the Fundamental Research Funds for the Central Universities(No.N2201005).
文摘Given the depletion of high-quality magnesite deposits and the rising demand for high-end magnesium materials,the separation and utilization of high-calcium magnesite ores have become essential.However,the similar surface properties and solubility of semi-soluble salt-type minerals,pose significant challenges for the utilization of dolomite-rich magnesite resources.In this study,1-hydroxypropane-1,1-di phosphonic acid(HPDP)was identified for the first time as a high-performance depressant for dolomite.Various tests,including contact angle measurements,ζ potential analysis,X-ray photoelectron spectroscopy,and atomic force microscopy,were conducted to elucidate the interfacial interaction mechanisms of HPDP on the surfaces of the two minerals at different scales.Additionally,molecular modeling calculations were used to detail the spatial matching relationship between HPDP and the crystal faces of the two minerals.It was emphasized that HPDP specifically adsorbed onto the dolomite surface by forming calcium phosphonate,ensuring that the dolomite surface remained hydrophilic and sank.Moreover,it was found that the adsorption strength of HPDP on the mineral surfaces depended on the activity of the metal sites and their spatial distribution.These findings provide a theoretical foundation for the molecular design of flotation reagents for high-calcium magnesite ores.
基金Funded by the Natural Science Foundation of Ministry of Housing and Urban-Rural Development of the People's Republic of China(No.2009-K4-27)
文摘An accelerated laboratory method（saturated ammonium nitrate solution immersion method） was used to analyze the degradation of cement decalcification process. By studying the changes of intensity, volume, elastic modulus, quality, p H value, the Ca/Si, and mineral phase, it could be found that the first cement decalcification degradation process was the decalcification of calcium hydroxide, and then CSH gel, AFm, etc. The secondary ettringite deposition happened and the decalcification degradation depth was proportional to the square root of time. Moreover, the corresponding strength of cement would be gradually reduced, cement rock volume shrinkage occurred, p H values decreased, the surface elastic modulus decreased down to a certain level, and slightly changed and the Ca/Si was 3.1 from the beginning and lasted down to 1.3.
基金supported by the National Key Research and Development Program of China(2018YFC1900206-2)Science&Technology Plan Projects of Guizhou Province(Qiankehe Service Enterprises[2018]4011)Science and Technology Support Plan Project of Guizhou Provincial:Qiankehe Support[2021]General 487。
文摘The freezing acidolysis solution of the nitric acid-phosphate fertilizer process has a high calcium content,which makes it difficult to produce fine phosphate and high water-soluble phosphate fertilizer products.Here,based on the potential crystallization principle of calcium sulfate in NH_(4)NO_(3)-H_(3)PO_(4)-H_(2)O,the deep decalcification(i.e.calcium removal)technology to achieveα-high-strength gypsum originated from freezing acidolysis-solutions has been firstly proposed and investigated.Typically,calcium can be removed from the factory-provided freezing acidolysis-solution by neutralizing it with ammonia,followed by the addition of ammonium sulfate solution.As a result,the formation of calcium sulfate in the reaction system undergoes the nucleation and growth of CaSO_(4)·2H_(2)O(DH),as well as its dissolution and crystallization into short columnarα-CaSO_(4)·0.5H_(2)O(α-HH).Remarkably,with the molar ratio of SO_(4)^(2-)/Ca^(2+)at 1.8,the degree of neutralization(NH_(3)/HNO_(3) molar ratio)at 1.7,the reaction temperature of 94℃,and the reaction time of 300 min,the decalcification rate can reach 86.89%,of which the high-strengthα-CaSO_(4)·0.5H_(2)O(α-HH)will be obtained.Noteworthy,the deep decalcification product meets the standards for the production of fine phosphates and highly water-soluble phosphate fertilizers.Consequently,the 2 h flexural strength ofα-HH is 5.3 MPa and the dry compressive strength is 36.8 MPa,which is up to the standard of commercialα-HH.
文摘Biological insecticides have gained importance in modern society because they cause minimal environmental harm and reduce pests’ability to develop resistance.Nomuraea rileyi,a facultative entomopathogenic fungus,is suitable for infecting lepidopteran pests,including Spodoptera litura and Helicoverpa armigera.This work aims to identify a suitable semi-solid fermentation medium to increase the conidia production of N.rileyi and enhance its biological control ability as mycoinsecticide.Research is carried out on broken rice,wheat,sorghum,and corn as substrates,both with and without nutrient addition.It also covers incubation under set conditions,colony harvesting,and conidial yield and germination determination using a haemocytometer.All the study was conducted using a completely randomized design(CRD)and a test of significance was set at p<0.05 using analysis of variance(ANOVA).This work aimed to establish the effect of various substrates on growth and conidia formation in N.rileyi.The highest conidia count of 10×10^(8)CFU/g on day 15.The result was obtained from BR+Nu followed by sorghum 7×10^(8)CFU/g,corn 7×10^(8)CFU/g and wheat 6.5×10^(8)CFU/g.Thus,post-drying,the highest corresponding viability was observed in the product containing BR+Nu–6.20×10^(8)CFU/g.Adding rice bran(BR+RB,150 g each)still increases conidial yield up to 14×10^(8) CFU/g at 15 DAI.These indings thus assert that broken rice and supplementation affect conidia yield and viability.
基金Supported by the University of Kelaniya Grant,No.RP/03/04/11/01/2011.
文摘BACKGROUND Routine assessment of solid gastric emptying is challenging due to the prolonged test duration and complex meal preparation.Replacing solid test meals with easily prepared,commercially available semisolid meals and shortening the test duration can significantly enhance the feasibility and practicality of gastric emptying evaluations.AIM To compare the gastric emptying and antral motility of solid vs semi-solid meals of similar volume and nutritional consistency,and to assess the feasibility of meal substitution and reduction in test duration during the solid gastric emptying assessment.METHODS Thirty healthy volunteers(17 males,age:29.4±6.0 years,body mass index:23.4±2.94 and 13 females,age:37.2±11.9 years,body mass index:22.9±4.34)underwent gastric emptying by real-time ultrasonography after a solid meal and a comparable commercially prepared semi-solid meal(each meal,total calorie 350 kcal,carbohydrates 60%,fat 30%and proteins 10%),on separate dates 1 week apart.The gastric antral area was measured at 5 minutes,15 minutes,30 minutes,45 minutes,60 minutes,90 minutes,120 minutes,150 minutes,180 minutes,210 minutes,and 240 minutes post-ingestion using a previously validated technique and compared between meals.RESULTS Mean and median antral areas,gastric emptying rates,gastric residual ratios,and motility index at each time point were almost similar between meals for up to 3 hours.At the end of 4 hours,the mean emptied percentage of the semisolid meal and solid meal was 81.1%and 70.6%,respectively.The emptying rate of the semisolid meal at 90 minutes significantly correlated with that of 240 minutes.There was no correlation between the solid meal emptying rates at 90 minutes and 240 minutes.CONCLUSION Gastric emptying,residual antral cross-sectional area and antral motility of a semisolid meal are almost similar to that of a solid meal of the same nutritional value until three hours post-ingestion.A semisolid test meal can effectively substitute a solid test meal during ultrasound assessment of gastric emptying,without compromising the validity of the results.Additionally,the ease of preparation and administration of semisolid meals enhances the overall feasibility of gastric emptying assessments.
基金the financial support from Basic Research Projects of Higher Education Institutions of Liaoning Province(Key Research Projects)(No.JYTZD2023108)General Project of Liaoning Provincial Department of Education(Nos.LJKMZ20220462 and JYTMS20231199).
文摘Through the innovative integration of semi-solid rheo-casting with extrusion shear process,the short-process fabrication of low-alloyed wrought Mg-2Zn-1Mn alloy is achieved in this study.Uniaxial tensile testing of low-temperature extrusion shear specimens(200℃)demonstrates the exceptional strength-ductility synergy,yield strength of 277 MPa,yield strength ratio of 0.95,and elongation of 24%.Microstructural observations reveal the mechanisms underlying its high strength-plasticity synergy at room temperature.This study investigates the effects of different temperature gradients on the microstructure by analyzing experiments conducted at three temperatures:300℃,250℃,and 200◦C.Ultimately,the formation mechanism of the bimodal microstructure obtained at 200℃ is elucidated.The distinctive crystallographic texture oriented at 34°relative to the loading axis direction effectively mitigates stress concentration by inducing the synergistic activation of multiple slip systems.Furthermore,the transition trends of different slip systems and texture evolution during tensile deformation are validated through Visco-Plastic Self-Consistent(VPSC)simulations and corroborated by microstructural analysis.With geometrically necessary dislocation(GND)density(4.28×10^(15)m^(-2))and pyramidal slip activation(~45%).This study has successfully broken through the bottleneck of strength-ductility trade-off in magnesium alloys,providing theoretical support for the development of high-reliability magnesium alloys.
基金supported by the National Key R&D Projects(No.2021YFB3702000)the Institute Projects of Ansteel Beijing Research Institute(No.2023BJC-06)the Regional Company Projects in Ansteel Beijing Research Institute(No.2022BJB-18BG&No.2022BJB-13GF).
文摘The Al-Mg_(2)Si in-situ composite is a lightweight material with great potential for application in fields such as automotive lightweighting,aerospace,and electronic components.In this research,the modification,semi-solid technology coupled with different types of electromagnetic stirring was applied to regulate the undesirable solidified dendritic microstructure and facilitate the composites’mechanical properties.The spheroidization and refinement of Mg_(2)Si andα-Al matrix in SM(semi-solid)+RES(rotate electromagnetic stirring)sample and SM+SHES(single winding helical electromagnetic stirring)sample are realized under the effect of fused dendrite arm,the decreased critical nucleate radius,and the increased nucleation rate and extra supercooling degree induced by electromagnetic stirring.The Mg_(2)Si phase in the SM+RES sample and SM+SHES sample is refined by 73.4%and 75.7%,respectively compared to the AC(as-cast)sample.Besides,the single winding electromagnetic stirring can lead to more homogeneously distributed physical fields,lower temperature gradient,and more significant mass transfer,mainly responsible for the more homogeneous distributed reinforced finer Mg_(2)Si particles in the SM+SHES sample.Moreover,both the tensile properties and hardness of modified semi-solid composites are improved through electromagnetic stirring.Compared with RES,the improvement effect of SHES is more excellent.The SM+SHES sample possesses the highest Brinell hardness(124.7 HB),and its quality index of tensile properties is 5.73%and 82.2%higher than that of the SM+RES and AC samples,respectively.
基金Project(51335009)supported by the National Natural Science Foundation of ChinaProject(2014JQ7273)supported by the Natural Science Foundation of Shaanxi Province of ChinaProject(CXY1514(1))supported by the Xi’an Science and Technology Plan Projects,China
文摘Semi-solid squeeze casting（SSSC） and liquid squeeze casting（LSC） processes were used to fabricate a ZL104 connecting rod, and the influences of the process parameters on the microstructures and mechanical properties were investigated. Results showed that the tensile strength and elongation of the SSSC-fabricated rod were improved by 22% and 17%, respectively, compared with those of the LSC-fabricated rod. For SSSC, the average particle size（APS） and the shape factor（SF） increased with the increase of re-melting temperature（Tr）, whereas the tensile strength and elongation increased first and then decreased. The APS increased with increasing the mold temperature（Tm）, whereas the SF increased initially and then decreased, which caused the tensile strength and elongation to increase initially and then decrease. The APS decreased and the SF increased as squeezing pressure（ps） increased, and the mechanical properties were enhanced. Moreover, the optimal Tr, ps and Tm are 848 K, 100 MPa and 523 K, respectively.
基金Project(2011M500772)supported by China Postdoctoral Science Foundation of ChinaProject(2007CB613701)supported by the National Basic Research Program of ChinaProject(2009AA033501)supported by the National High-tech R&D Program of China
文摘The effects of cooling conditions on the microstructure of semi-solid AZ91 slurry produced via ultrasonic vibration process were investigated. AZ91 melts were subjected to ultrasonic vibration in different temperature ranges under different cooling rates. The results show that fine and spherical α-Mg particles are obtained under ultrasonic vibration at the nucleation stage, which is mainly attributed to the cavitation and acoustic streaming induced by the ultrasonic vibration. The reduction of lower limit of ultrasonic vibration temperature between the liquidus and solidus increases the solid volume fraction and average particle size. Increasing cooling rate increases the solid volume fraction and reduces the average shape factor of particles. The appropriate temperature range for ultrasonic vibration is from 605 °C to 595 °C or 590 °C, and the suitable cooling rate is 2-3 °C/min.
基金Projects (2005CCA06400, 2007CB613807) supported by the National Basic Research Program of China Project (CHD2010JC115) supported by the Special Fund for Basic Scientific Research of Central Colleges,China
文摘Microstructure evolution of Ti14 （α＋Ti2Cu） alloy during semi-solid isothermal process at different temperatures was investigated. The results reveal that both the temperature and holding time have effect on the grain growth behavior. The grains grow obviously and the degree of globularity increases with the increase of holding time. According to the statistic analysis of experimental data, the grain growth indices are 0.88 and 0.97 at 1 000 ℃ and 1 050 ℃, respectively, which indicates that increasing isothermal temperature would accelerate microstructural evolution.
基金Project (2011CB606302-1) supported by the National Basic Research Program of China
文摘The semi-solid slurry of 7075 aluminum alloy was prepared by a serpentine pouring channel （SCP）. Influences of pouring temperature and the number of turns on the microstructure of semi-solid 7075 alloy slurry were investigated. The results demonstrated that the semi-solid 7075 aluminum alloy slurry with satisfied quality could be generated by a serpentine pouring channel when the pouring temperature was in the range of 680-700 ℃. At a given pouring temperature, the equivalent size of the primaryα（Al） grains decreased and the shape factor increased with the increase of the number of turns. During the slurry preparation of semi-solid 7075 aluminum alloy, the flow direction of alloy melt changed many times when it flowed in a curved and closed serpentine channel. With the effect of“stirring”in it , the primary nuclei gradually evolved into spherical and near-spherical grains.
基金Projects(50774026,50875059)supported by the National Natural Science Foundation of ChinaProject(20070420023)supported by the China Postdoctoral Science FoundationProject(2008AA03A239)supported by the High-tech Research and Development Program of China
文摘The inhomogeneity of density and mechanical properties of A357 aluminum alloy in the semi-solid state were investigated.Numerical simulation and backward extrusion were adopted to study the preparation of cup shells.The results show that the relative density of the wall is the lowest in samples,and that of the base is the highest.With increasing the billet height,more time is needed for relative density of the corner to reach the maximum value,and the relative densities in every region improve evidently with increasing the pressure.The tensile stress was simulated to be the largest at the corner,and the hot tearings were forecasted to mainly appear at the corner too.By employing proper billet height and pressure,the extruded samples consisted of fine and uniform microstructures,and can obtain excellent mechanical properties and Brinell hardness.
基金Project (2011CB606302-1) supported by the National Basic Research Program of ChinaProject (51074024) supported by the National Natural Science Foundation of China
文摘Semi-solid 7075 Al slurry was prepared by inverted cone-shaped pouring channel process （ICSPC） and temperature homogenization （TH） treatment was combined to make the slurry uniform and have a controllable solid fraction suitable for the follow-up rheocasting. The influence of cooling rate on the microstructure evolution of primary α（Al） during TH treatment was investigated. The results show that as the cooling rate of the slurry after being prepared reduces, the growth of primaryα（Al） in the slurry tends to be nearly spherical and the uniformity of the organization is also enhanced. This may be due to the fact that lower cooling rate plays an important role in achieving the uniformity of temperature and composition in the remaining liquid, which is crucial to the formation of the spherical and homogeneous microstructure. However, a too low cooling rate will lead to a significant increase in grain growth time, which makes too coarse grains and more particles coalesce, so a certain abnormal growth of grain appears and the shape factor decreases slightly.
文摘The electronic packaging box with high silicon aluminum-base alloy was prepared by semi-solid thixoforming technique.The flow characteristic of the Si phase was analyzed.The microstructures of different parts of the box were observed by optical microscopy and scanning electron microscopy,and the thermophysical and mechanical properties of the box were tested.The results show that there exists the segregation phenomenon between the primary Si phase and the liquid phase during thixoforming,the liquid phase flows from the box,and the primary Si phase accumulates at the bottom of the box.The volume fraction of primary Si phase decreases gradually from the bottom to the walls.Accordingly,the thermal conductivities of bottom center and walls are 107.6 and 131.5 W/（m·K）,the coefficients of thermal expansion（CTE） are 7.9×10-6 and 10.6×10-6 K-1,respectively.The flexural strength increases slightly from 167 to 180 MPa.The microstructures and properties of the box show gradient distribution overall.
基金Project (2006AA03Z115) supported by the National High-tech Research and Development Program of ChinaProject (2006CB605203) supported by the National Basic Research Program of ChinaProject (50774007) supported by the National Natural Science Foundation of China
文摘Semi-solid A356 aluminum alloy slurry was prepared by using serpentine channel pouring process, and the influences of the channel diameters and pouring temperatures on the semi-solid A356 aluminum alloy slurry were investigated. The experimental results show that when the channel diameter is 20 and 25 mm, respectively, and the pouring temperature is 640-680 ℃, the average diameter of primary α（Al） grains in the prepared A356 aluminum alloy slurry is 50-75 and 55-78 μm, respectively, and the average shape factor of primary α（Al） grains is 0.89-0.76 and 0.86-0.72, respectively. With the decline in the pouring temperature, the microstructure of semi-solid A356 aluminum alloy slurry is more desirable and a serpentine channel with smaller diameter is also advantageous to the microstructure imProvement. During the preparation of semi-solid A356 aluminum alloy slurry, a large number of nuclei can be produced by the chilling effect of the serpentine channel, and owing to the combined effect of the chilled nuclei separation and melt self-stirring, primary α（Al） nuclei can be multiplied and spheroidized finally.
基金Project(2011CB606300)supported by the National Basic Research Program of ChinaProject(5077400)supported by the National Natural Science Foundation of China
文摘The semi-solid slurry of A380 aluminum alloy was prepared by the serpentine channel. The effects of pouring temperature, curve number and curve diameter of the serpentine channel on the microstructure of the semi-solid A380 aluminum alloy slurry were investigated. The results show that the satisfactory semi-solid A380 aluminum alloy slurry could be obtained when the pouring temperature ranged from 630 to 650 °C. Under the same conditions, increasing the curve number or reducing the curve diameter of the serpentine channel would decrease the average diameter and increase the shape factor of the primary α（Al） grains. The ＂self-stirring＂ of the alloy melt in the serpentine channel was beneficial to the ripening of the dendrites and the spheroidizing of the primary α（Al） grains.
文摘The microstructural evolution of AZ91D magnesium alloy prepared by means of the cyclic upsetting-extrusion and partial remelting was investigated. The effects of remelting temperature and holding time on microstructure of semi-solid AZ91D magnesium alloy were studied. Furthermore, tensile properties of thixoextruded AZ91D magnesium alloy components were determined. The results show that the cyclic upsetting-extrusion followed by partial remelting is effective in producing semi-solid AZ91D magnesium alloy for thixofonning. During the partial remelting, with the increase of remelting temperature and holding time, the solid grain size increases and the degree of spheroidization tends to be improved. The tensile mechanical properties of thixoextruded AZ91D magnesium alloy components produced by cyclic upsetting-extrusion and partial remelting are better than those of the same alloy produced by casting.
基金Project(51275295)supported by the National Natural Science Foundation of ChinaProjects(20120073120011,20130073110052)supported by the Research Fund for the Doctoral Program of Higher Education of China
文摘The semi-solid slurry of AZ91 D magnesium alloy was prepared by gas bubbling process.The effect of processing parameters,including gas flow rate,cooling rate and stirring end temperature,on microstructure of AZ91 D semi-solid slurry was investigated.With increasing the gas flow rate from 0 to 5 L/min,the average size of primary α-Mg particles decreases from 119.1 to77.2μm and the average shape factor increases continuously from 0.1 to 0.596.The formation of non-dendritic primary α-Mg particles during gas bubbling is the result of combined effects of dendrite fragmentation and copious nucleation.With increasing the cooling rate from 3.6 to 14.6℃/min,the average particle size of primary α-Mg phase decreases from 105.0 to 68.1μm while the average shape factor peaks at 9.1℃/min.Both high and low cooling rates can induce dendritic growth of primary α-Mg particles.Changing the stirring end temperature from 590 to 595℃ has little effect on the average size and shape factor of primary α-Mg particles in AZ91 D semi-solid slurry.The insensitivity of semi-solid microstructures to the stirring end temperature is attributed to the sufficient quantity of primary particles formed in the melt.
基金Project(51405100)supported by the National Natural Science Foundation of ChinaProject(2014M551233)supported by the Postdoctoral Science Foundation of China+1 种基金Project(2014-HT-HGD12)supported by the Astronautical Supporting Technology Foundation of ChinaProject(2015GGX102023)supported by the Plan of Science and Technology Development in Shandong Province,China
文摘In order to study the hot fractures in relation to the semi-solid processing, the tensile tests of an extruded 7075 aluminum alloy which is based on Al?Zn?Mg?Cu system were carried out in the high temperature solid and semi-solid states at different strain rates. The results show that the tensile behavior can be divided into three regimes with increasing the liquid fraction. The alloy first behaves in a ductile character, and as the temperature increases, the fracture mechanism changes from ductile to brittle which is determined by both of liquid and solid, and lastly the fracture mechanism is brittle which is totally dominated by liquid. At strain rates of 1×10?4, 1×10?3 and 1×10?2 s?1, the brittle temperature ranges are 515?526, 519?550 and 540?580 °C, respectively. Two equations which are critical for tensile behavior are proposed.
