The significant demand for high quality food has motivated us to adopt appropriate processing methods to improve the food nutritional quality and flavors.In this study,the effects of five drying methods,namely,pulsed ...The significant demand for high quality food has motivated us to adopt appropriate processing methods to improve the food nutritional quality and flavors.In this study,the effects of five drying methods,namely,pulsed vacuum drying(PVD),freeze drying(FD),infrared drying(IRD),hot-air drying(HAD)and sun drying(SD)on free amino acids(FAAs),α-dicarbonyl compounds(α-DCs)and volatile compounds(VOCs)in rape bee pollen(RBP)were determined.The results showed that FD significantly released the essential amino acids(EAAs)compared with fresh samples while SD caused the highest loss.Glucosone was the dominantα-DCs in RBP and the highest loss was observed after PVD.Aldehydes were the dominant volatiles of RBP and SD samples contained more new volatile substances(especially aldehydes)than the other four drying methods.Comprehensively,FD and PVD would be potential methods to effectively reduce the quality deterioration of RBP in the drying process.展开更多
As an important factor that directly affects agricultural production, the social economy, and policy implementation,observed changes in dry/wet conditions have become a matter of widespread concern. However, previous ...As an important factor that directly affects agricultural production, the social economy, and policy implementation,observed changes in dry/wet conditions have become a matter of widespread concern. However, previous research has mainly focused on the long-term linear changes of dry/wet conditions, while the detection and evolution of the non-linear trends related to dry/wet changes have received less attention. The non-linear trends of the annual aridity index, obtained by the Ensemble Empirical Mode Decomposition(EEMD) method, reveal that changes in dry/wet conditions in China are asymmetric and can be characterized by contrasting features in both time and space in China. Spatially, most areas in western China have experienced transitions from drying to wetting, while opposite changes have occurred in most areas of eastern China. Temporally, the transitions occurred earlier in western China compared to eastern China. Research into the asymmetric spatial characteristics of dry/wet conditions compensates for the inadequacies of previous studies, which focused solely on temporal evolution;at the same time, it remedies the inadequacies of traditional research on linear trends over centennial timescales. Analyzing the non-linear trend also provides for a more comprehensive understanding of the drying/wetting changes in China.展开更多
Experiments were conducted to evaluate the healing of drying cracks in air-dried bentonite-sand blocks after hydration and swelling in groundwater,providing justifications to simplify the protection of blocks prior to...Experiments were conducted to evaluate the healing of drying cracks in air-dried bentonite-sand blocks after hydration and swelling in groundwater,providing justifications to simplify the protection of blocks prior to installation in a high-level radioactive waste repository.Synthetic groundwater was prepared to represent the geochemistry of Beishan groundwater,and was used to hydrate the blocks during the swelling pressure and swelling strain measurements,as Beishan is the most promising site for China's repository.Healing of the surface cracks was recorded by photography,and healing of the internal cracks was visualized by CT images and hydraulic conductivity of air-dried blocks.The results indicate that the maximum swelling pressure and swelling strain are primarily affected by the geochemistry of Beishan groundwater,but not affected by the drying cracks.The maximum swelling pressure and swelling strain of air-dried blocks are comparable to or even higher than the pressure and strain of fresh blocks.The maximum swelling pressure measured in strong(i.e.high ion strength)Beishan groundwater was 44%of the pressure measured in deionized(DI)water,and the maximum swelling strain was reduced to 23%of the strain measured in DI water.Nevertheless,the remained swelling of the blocks hydrated in strong Beishan groundwater was sufficient to heal the surface and internal drying cracks,as demonstrated by the pictures of surface cracks and CT images.The hydraulic conductivity of the air-dried block permeated with strong groundwater was comparable(3.7×higher)to the hydraulic conductivity of the fresh block,indicating the self-healing of drying cracks after hydration and swelling in groundwater.A simplified method of protecting the block with plastic wraps before installation is recommended,since the remained swelling of the block hydrated in Beishan groundwater is sufficient to heal the drying cracks.展开更多
Lysine content is a criterion of the nutritional quality of rice.Understanding the process of lysine biosynthesis in early-flowering superior grain(SG)and late-flowering inferior grain(IG)of rice would advance breedin...Lysine content is a criterion of the nutritional quality of rice.Understanding the process of lysine biosynthesis in early-flowering superior grain(SG)and late-flowering inferior grain(IG)of rice would advance breeding and cultivation to improve nutritional quality.However,little information is available on differences in lysine anabolism between SG and IG and the underlying mechanism,and whether and how irrigation regimes affect lysine anabolism in these grains.A japonica rice cultivar was grown in the field and two irrigation regimes,continuous flooding(CF)and wetting alternating with partial drying(WAPD),were imposed from heading to the mature stage.Lysine content and activities of key enzymes of lysine biosynthesis,and levels of brassinosteroids(BRs)were lower in the IG than in the SG at the early grainfilling stage but higher at middle and late grain-filling stages.WAPD increased activities of these key enzymes,BR levels,and contents of lysine and total amino acids in IG,but not SG relative to CF.Application of 2,4-epibrassinolide to rice panicles in CF during early grain filling reproduced the effects of WAPD,but neither treatment altered the activities of enzymes responsible for lysine catabolism in either SG or IG.WAPD and elevated BR levels during grain filling increased lysine biosynthesis in IG.Improvement in lysine biosynthesis in rice should focus on IG.展开更多
Appropriate drying process with optimized controlling of drying parameters plays a vital role in the improvement of the quality and performance of propellant products.However,few research on solvent transport dynamics...Appropriate drying process with optimized controlling of drying parameters plays a vital role in the improvement of the quality and performance of propellant products.However,few research on solvent transport dynamics within NC-based propellants was reported,and its effect on the evolution of mechanical properties was not interpreted yet.This study is conducted to gain a comprehensive understanding of hot-air drying for NC-based propellants and clarify the effect of temperature on solvent transport behavior and further the change of mechanical properties during drying.The drying kinetic curves show the drying time required is decreased but the steady solvent content is increased and the drying rate is obviously increased with the increase of hot-air temperatures,indicating hot-air temperatures have a significant effect on drying kinetics.A modified drying model was established,and results show it is more appropriate to describe solvent transport behavior within NC-based propellants.Moreover,two linear equations were established to exhibit the relationship between solvent content and its effect on the change of tensile properties,and the decrease of residual solvent content causes an obvious increase of tensile strength and tensile modulus of propellant products,indicating its mechanical properties can be partly improved by adjustment of residual solvent content.The outcomes can be used to clarify solvent transport mechanisms and optimize drying process parameters of double-based gun propellants.展开更多
The dried roots of Aconitum pendulum Busch are the major source of a commonly used Tibetan medicine,namely Tiebangchui(TBC)(Fig.S1).However,raw TBC contains a large amount of high toxic diester-diterpenoid alkaloids(D...The dried roots of Aconitum pendulum Busch are the major source of a commonly used Tibetan medicine,namely Tiebangchui(TBC)(Fig.S1).However,raw TBC contains a large amount of high toxic diester-diterpenoid alkaloids(DDAs),and the improper use would cause arrhythmia,irreversible cardiovascular damages,and even death.“Paozhi”,an appropriate processing method,is the essential prerequisite for the safe clinical application of TBC.Water-decocting and sand-frying are commonly used processing methods for toxicity attenuation and efficacy preservation for TBC.展开更多
Adjusting agronomic measures to alleviate the kernel position effect in maize is important for ensuring high yields.In order to clarify whether the combined application of organic fertilizer and chemical fertilizer(CA...Adjusting agronomic measures to alleviate the kernel position effect in maize is important for ensuring high yields.In order to clarify whether the combined application of organic fertilizer and chemical fertilizer(CAOFCF)can alleviate the kernel position effect of summer maize,field experiments were conducted during the 2019 and 2020 growing seasons,and five treatments were assessed:CF,100%chemical fertilizer;OFCF1,15%organic fertilizer+85%chemical fertilizer;OFCF2,30%organic fertilizer+70%chemical fertilizer;OFCF3,45%organic fertilizer+55%chemical fertilizer;and OFCF4,60%organic fertilizer+40%chemical fertilizer.Compared with the CF treatment,the OFCF1 and OFCF2 treatments significantly alleviated the kernel position effect by increasing the weight ratio of inferior kernels to superior kernels and reducing the weight gap between the superior and inferior kernels.These effects were largely due to the improved filling and starch accumulation of inferior kernels.However,there were no obvious differences in the kernel position effect among plants treated with CF,OFCF3,or OFCF4 in most cases.Leaf area indexes,post-silking photosynthetic rates,and net assimilation rates were higher in plants treated with OFCF1 or OFCF2 than in those treated with CF,reflecting an enhanced photosynthetic capacity and improved postsilking dry matter accumulation(DMA)in the plants treated with OFCF1 or OFCF2.Compared with the CF treatment,the OFCF1 and OFCF2 treatments increased post-silking N uptake by 66.3 and 75.5%,respectively,which was the major factor driving post-silking photosynthetic capacity and DMA.Moreover,the increases in root DMA and zeatin riboside content observed following the OFCF1 and OFCF2 treatments resulted in reduced root senescence,which is associated with an increased post-silking N uptake.Analyses showed that post-silking N uptake,DMA,and grain yield in summer maize were negatively correlated with the kernel position effect.In conclusion,the combined application of 15-30%organic fertilizer and 70-85%chemical fertilizer alleviated the kernel position effect in summer maize by improving post-silking N uptake and DMA.These results provide new insights into how CAOFCF can be used to improve maize productivity.展开更多
AIM:To explore ocular surface manifestations of dry eye disease(DED)and its influencing factors in systemic lupus erythematosus(SLE)patients.METHODS:Ophthalmological examinations were conducted in SLE patients(n=43)an...AIM:To explore ocular surface manifestations of dry eye disease(DED)and its influencing factors in systemic lupus erythematosus(SLE)patients.METHODS:Ophthalmological examinations were conducted in SLE patients(n=43)and controls(n=41),including Ocular Surface Disease Index(OSDI),objective scatter index(OSI),tear meniscus height(TMH),lipid layer thickness(LLT),non-invasive Keratograph tear breakup time(NIKBUT),corneal fluorescein score(CFS),Schirmer I test.DED was diagnosed according to the Tear Film and Ocular Surface Society Dry Eye Workshop II Criteria.SLE patients were further divided into DED group and non-DED group,the disease activity,clinical manifestations and laboratory investigations were compared between the two groups.The disease activity was evaluated by Systemic Lupus Erythematosus Disease Activity Index 2000(SLEDAI-2K).Receiver operative characteristic(ROC)curve and multiplefactor binary logistic regression were performed.RESULTS:SLE patients showed higher OSDI[9.1(2.8-15.9)vs 6.3(2.2-7.5),P=0.035],higher OSI[1.67(1.09-2.60)vs 0.96(0.87-1.60),P=0.001],higher CFS[1(0-2)vs 0(0-1),P=0.001],lower LLT[65(42-100)vs 100(79.5-100),P=0.010],and lower NIKBUT[8.03(4.02-9.73)vs 9.67(5.26-12.71),P=0.030]than controls.The 32.6%of SLE patients had DED,which was higher than 12.2%of healthy controls.DED group showed higher SLEDAI-2K score[9.7±6.1 vs 5.4±3.4,P=0.025],higher anti-cardiolipin antibody(ACL)[8.7(3.5-13.2)vs 3.6(2.0-6.9),P=0.035],and higher proportion of patients with cutaneous eruption[42.9%vs 6.9%,P=0.015]than non-DED group.According to multiple-factor binary logistic regression analysis,the SLEDAI-2K score(OR=1.194,P=0.041)and cutaneous eruption(OR=7.094,P=0.045)could be consider as risk factors for DED in SLE patients.The ROC curve of the combined factors including age,disease duration,SLEDAI-2K score,ACL,and cutaneous eruption was analyzed,with a sensitivity of 0.786,a specificity of 0.793,and an area under curve of 0.820.CONCLUSION:Ocular surface affection is frequent in SLE patients,and patients with high disease activity and cutaneous eruption show increased risk of DED.展开更多
The development of microbial-based products requires certain criteria for them to be successfully commercialized. The product must meet the following desirable criteria: effectiveness, contamination free, stability, c...The development of microbial-based products requires certain criteria for them to be successfully commercialized. The product must meet the following desirable criteria: effectiveness, contamination free, stability, cost-effectiveness, and a prolonged shelf life. Controlling the drying process is crucial for ensuring the stability and durability of the product. The traditional approach, which involved mechanical and natural drying, led to decreased productivity and quality. The objective of this research endeavour was to achieve a dry process enhancement while preserving the microbial quality of Trichoderma asperellum (M103). The temperature and relative humidity during the drying period were monitored under two conditions: with and without a dehumidifier. The results demonstrate that the dehumidifier increases drying period efficiency by up to 63%.展开更多
Monolithic refractory castables comprising a hydraulic bond are still used in a vast majority of cases because of their flexibility and robustness,despite many developments for chemical as well as non-cement castable ...Monolithic refractory castables comprising a hydraulic bond are still used in a vast majority of cases because of their flexibility and robustness,despite many developments for chemical as well as non-cement castable binders.The drying can however be a challenge,in particular for deflocculated dense castables of the low cement castable range.Many publications have been released on this topic for the last ten years,but they often focused on the drying mechanisms or on the addition of drying aids.This paper presents some experimental results on the effect of the composition on the drying properties,especially on the effect of silicon carbide,used for its high thermal conductivity,and on the matrix system.It also introduces two laboratory tests to study and iteratively improve the drying schedule of a given castable lining.The results show that the spalling resistance and the vapor pressure build-up are significantly influenced by the formulation.It is also shown that the castable properties after drying can be altered if the heating rate is very high.展开更多
Refractories have unique capabilities such as sustaining their shape and properties at extreme conditions such as the combination of high temperatures and thermal shock,contact with molten metals and slags and in some...Refractories have unique capabilities such as sustaining their shape and properties at extreme conditions such as the combination of high temperatures and thermal shock,contact with molten metals and slags and in some circumstances resistance to erosion from abrasive particles.Given the large processing output of the heavy industries such as the cement and steel ones which both require high temperature processes,the refractories structures span various meters and weight of several tons.As the water removal stage of hydraulic bonded castables in industrial sites takes hours(10-60 h)due to the risk of explosive spalling,efforts to mitigate it are commonly studied.This has provided theoretical understanding of the general aspects of drying and important tools,such as the thermogravimetry analysis(TGA),for the design of refractory compositions with higher explosive spalling resistance.However,the optimization of this process is still far from the industrial reality especially because the actual linings that require the drying are orders of magnitude larger than the samples considered in the laboratory tests.Therefore,this study proposed the analysis of the sample volume effect on the water removal dynamics through TGA of high alumina castables with calcium aluminate cement.Conventionalφ5 cm×5 cm cylindrical samples were assessed in a laboratory scale equipment whereas macro TGA were carried out considering 20 cm×20 cm×20 cm and 30 cm×30 cm×30 cm cubic samples.Additionally,the effect of polymeric fibers was also considered.It was found out that the different thermal gradients within the macro TGA samples resulted in an inflection on the sample’s heating rate and that the mass loss was affected by the volume considered,especially for the composition without additives.These findings highlight the requirement of carefully taking into consideration the different dimensional sizes and thermal gradients in the samples when analyzing and interpreting the laboratory studies,and especially when trying to extrapolate such results to the industrial reality.展开更多
Under the current context of climate change, supplementary irrigation may be needed for crop production resilience. We determined the effects of supplementary irrigation on sorghum grain yield in the dry Savannah regi...Under the current context of climate change, supplementary irrigation may be needed for crop production resilience. We determined the effects of supplementary irrigation on sorghum grain yield in the dry Savannah region of Togo. A two-year trial was conducted in a controlled environment at AREJ, an agro-ecological center in Cinkassé. The plant material was sorghum variety Sorvato 28. The experimental design was a Completely Randomized Block with three replications and three treatments as follows: T0 control plot (rainfed conditions);T1 (supplementary irrigation from flowering to grain filling stage) and T2 (supplementary irrigation from planting to grain filling stage). Two irrigation techniques (furrow and Californian system) were used under each watering treatment. The results showed that irrigation technique significantly affected panicle length with no effect on 1000 grains mass. Panicle length and grain yields varied from 15.59 to 25.71 cm and 0.0 to 2.06 t∙h−1, respectively, with the highest values (25.66 cm and 2.06 t∙h−1, respectively) under the T2 treatment with the California system-based supplementary irrigation. The comparison of results obtained on treatment T0 and T2, shows that supplementary irrigation increased the yields by at least 68.62%. Supplementary irrigation during sowing and growing season (T2) improved sorghum yields in the dry savannahs of Togo, with a better performance of the California irrigation system.展开更多
Background: Dry eye and glaucoma are two common pathologies in the elderly, and are very often associated. This association suggests a link between them and between their treatments. Our purpose for this study is to d...Background: Dry eye and glaucoma are two common pathologies in the elderly, and are very often associated. This association suggests a link between them and between their treatments. Our purpose for this study is to determine the prevalence of dry eye in our glaucoma patients treated with eye drops and deduce the factors associated with it. Patients and Methods: We conducted a cross-sectional, analytical study from October 2022 to September 2023 in the ophthalmology department of Garoua Regional Hospital in glaucoma patients aged over 15 years able to answer the Ocular Surface Disease Index (OSDI) questionnaires and treated with antiglaucoma eye drops for more than 3 months. These patients underwent a complete ophthalmological examination and a tear film break-up time test. Results: A total of 73 patients (146 eyes) were examined. The average age of the patients was 47.2 ± 16.5 years, with a male predominance of 54.8%. The prevalence of dry eye syndrome in our patients according to the OSDI score was 56.2% (95% CI) (44.8;67.6). The prevalence of dry eye syndrome on clinical examination of the BUT in the right eye was 83.7% (95% CI) (75.1;92.1) and 79.4% (70.2;88.7) in the left eye. The duration of antiglaucoma treatment was the factor associated with dry eye syndrome (p < 0.05) in glaucoma patients in our setting. Conclusion: Dry Eye Syndrome is common in glaucoma patients on drops in our setting. Treatment duration of more than 1 year seems to be associated with dry eyes.展开更多
This study is an extension of the previous work done with ARS-680 Environmental Chamber. Drying is a complex operation that demands much energy and time. Drying is essentially important for preservation of ginger rhiz...This study is an extension of the previous work done with ARS-680 Environmental Chamber. Drying is a complex operation that demands much energy and time. Drying is essentially important for preservation of ginger rhizome. Drying of ginger was modeled, and then the effective diffusion coefficient and activation energy were determined. For this purpose, the experiments were done at six levels of varied temperatures: 10°C, 20°C, 30°C, 40°C, 50°C and 60°C. The values of effective diffusion coefficients obtained in this work for the variously treated ginger rhizomes closely agreed with the average effective diffusion coefficients of other notable authors who determined the drying kinetics and convective heat transfer coefficients of ginger slices.展开更多
We set out to model the oven-drying kinetics of a legume known as pigeon pea, harvested in the Bouenza department in the south-west of the Republic of Congo. The drying kinetics of pigeon peas was carried out in an ov...We set out to model the oven-drying kinetics of a legume known as pigeon pea, harvested in the Bouenza department in the south-west of the Republic of Congo. The drying kinetics of pigeon peas was carried out in an oven under experimental conditions using temperatures of: 50°C, 60°C and 70°C. Seven mathematical models were used to describe pigeon pea drying. During drying, water loss was faster and shorter at 70°C [10.446 g/25 g wet weight (wwb) for 320 min (5.3 h)] compared to 50°C [10.996 g/25 g wet weight (wwb) for 520 min (8.6 h)] and 60°C [10.616 g/25 g wet weight (wwb) for 420 min (7.0 h)] where it was slower and longer. With regard to modeling, and based on the principle of choosing the right model focusing on the high value of R2 and low values of χ2 and RMSE, two models were selected, the Midili model for temperatures of 50°C and 60°C and the Henderson and Pabis model modified for temperature of 70°C showed better results. The R2, χ2 and RMSE values calculated for pigeon pea are 0.99985, 3.93404E-5 and 0.00627;0.9997, 9.245E-5 and 0.00962;0.99996, 1.56332E-5 and 0.00395 respectively at 50°C, 60°C and 70°C.展开更多
This study investigated if super rice could better cope with soil water deficit and if it could have better yield performance and water use efficiency (WUE) under alternate wetting and drying (AWD) irrigation than...This study investigated if super rice could better cope with soil water deficit and if it could have better yield performance and water use efficiency (WUE) under alternate wetting and drying (AWD) irrigation than check rice. Two super rice cultivars and two elite check rice cultivars were grown in pots with three soil moisture levels, well watered (WW), moderate water deficit (MWD) and severe water deficit (SWD). Two cultivars, each for super rice and check rice, were grown in field with three irrigation regimes, alternate wetting and moderate drying (AWMD), alternate wetting and severe drying (AWSD) and conventional irrigation (CI). Compared with that under WW, grain yield was significantly decreased under MWD and SWD treatments, with less reduction for super rice than for check rice. Super rice had higher percentage of productive tillers, deeper root distribution, higher root oxidation activity, and greater aboveground biomass production at mid and late growth stages than check rice, especially under WMD and WSD. Compared with CI,AWMD increased, whereasAWSD decreased grain yield, with more increase or less decrease for super rice than for check rice. Both MWD and SWD treatments and eitherAWMD orAWSD regime significantly increased WUE compared with WW treatment or CI regime, with more increase for super rice than for check rice. The results suggest that super rice has a stronger ability to cope with soil water deficit and holds greater promising to increase both grain yield and WUE by adoption of moderate AWD irrigation.展开更多
Supported metal catalysts play a vital role in the chemical industry, and the metal-support interaction is an important property of the catalyst. However, in the traditional impregnation method, it is difficult to obt...Supported metal catalysts play a vital role in the chemical industry, and the metal-support interaction is an important property of the catalyst. However, in the traditional impregnation method, it is difficult to obtain sufficient metal-support interactions owing to the mobility of the metal precursor during evaporation drying. Here, freeze drying is applied during impregnation instead of evaporation drying for enhancing the metal-support interactions. 57 Fe ZSM-5 was chosen as a representative catalyst. A quantitative analysis was conducted based on Mossbauer spectroscopy. Compared with traditional evaporation-drying catalyst, freeze-drying catalyst has stronger metal-support interactions. In addition, more iron species are confined in the channel and smaller metal sizes and less diversity are obtained. The compositional change is also proved because of the superior performance of the freeze-drying catalyst during N2O decomposition. This method can be extended to other supported metal catalysts prepared through an impregnation method, which can be used to tune the metal-support interactions and metal sizes.展开更多
In kiln drying of softwood timber, external heat and moisture mass transfercoefficients are important in defining boundary temperature and moisture content at the woodsurface. In addition, superheated steam drying of ...In kiln drying of softwood timber, external heat and moisture mass transfercoefficients are important in defining boundary temperature and moisture content at the woodsurface. In addition, superheated steam drying of wood is a promising technology but this has notbeen widely accepted commercially, partially due to the lack of understanding of the dryingphenomena occurred during drying. In this work, experimental investigation was performed to quantifythe heat transfer between wood surface and surrounding moist air or superheated steam. In theexperiment, saturated radiata pine sapwood samples were dried using dry-bulb/wet-bulb temperaturesof 60℃/50℃, 90℃/60℃, 120℃/70℃, 140℃/90℃, 160℃/90℃, 140℃/100℃ and 160℃/100℃. The lasttwo schedules were for superheated steam drying as the wet-bulb temperature was set at 100℃. Thecirculation velocity over the board surface was controlled at 4.2m·s^(-1). Two additional runs(90℃/60℃) using air velocities of 2.4 m·s^(-1) and 4.8 m·s^(-1) were performed to check theeffect of the circulation velocity. During drying, sample weight and temperatures at wood surfaceand different depths were continuously measured. Prom these measurements, changes in woodtemperature and moisture content were calculated and external heat-transfer coefficient wasdetermined for both the moist air and the superheated steam drying.展开更多
We introduced a parameter r_s(the radius of the pores where the meniscus forms),which is composed of two factors,i e,water loss and cumulative pore size distribution(PSD),to provide a better explanation of the influen...We introduced a parameter r_s(the radius of the pores where the meniscus forms),which is composed of two factors,i e,water loss and cumulative pore size distribution(PSD),to provide a better explanation of the influence of superplasticizers(SPs)on early-age drying shrinkage.In our experiments,it is found that the addition of three types of SPs leads to a significant increase in the early-age drying shrinkage of cement paste,and drying shrinkage increases with the dosage of SPs.Based on the results above,we further studied the mechanism of the effects of SPs on the early-age drying shrinkage of cement paste by PSD and water loss,which are two components of r_s.The experimental results indicate that r_s can be a better index for the early-age drying shrinkage of cement-based materials with SPs than a single factor.In addition,the effects of SPs on other factors such as hydration degree and elastic modulus were also investigated and discussed.展开更多
TiO_2-CeO_2 nanocomposite particles were prepared with Ce(NO_3)_3·6H_2O and TiCl_4 as precursors by the codeposition method and supercritical fluid drying (SCFD) technology. The particles prepared were characteri...TiO_2-CeO_2 nanocomposite particles were prepared with Ce(NO_3)_3·6H_2O and TiCl_4 as precursors by the codeposition method and supercritical fluid drying (SCFD) technology. The particles prepared were characterized by means of XRD, TEM and FTIR. The results show that SCFD can give rise to the direct synthesis of the anatase TiO_2-CeO_2,and the particle size is 6~11 nm under 500 ℃ thermal-treated,smaller than that by common drying (CD). The phase transformation from anatase to rutile is inhibited by supercritical fluid drying technology. The peak of CeO_2 is not observed in XRD patterns,Ce-O band vibration was present in FTIR spectrum,which indicates that CeO_2 is well dispersed on the surface of TiO_2.展开更多
基金supported by National Natural Science Foundation of China(Nos.31871861 and 31501548)The Apicultural Industry Technology System(NCYTI-43-KXJ17)The Science and Technology Innovation Project of Chinese Academy of Agricultural Sciences(CAAS-ASTIP-2015-IAR)。
文摘The significant demand for high quality food has motivated us to adopt appropriate processing methods to improve the food nutritional quality and flavors.In this study,the effects of five drying methods,namely,pulsed vacuum drying(PVD),freeze drying(FD),infrared drying(IRD),hot-air drying(HAD)and sun drying(SD)on free amino acids(FAAs),α-dicarbonyl compounds(α-DCs)and volatile compounds(VOCs)in rape bee pollen(RBP)were determined.The results showed that FD significantly released the essential amino acids(EAAs)compared with fresh samples while SD caused the highest loss.Glucosone was the dominantα-DCs in RBP and the highest loss was observed after PVD.Aldehydes were the dominant volatiles of RBP and SD samples contained more new volatile substances(especially aldehydes)than the other four drying methods.Comprehensively,FD and PVD would be potential methods to effectively reduce the quality deterioration of RBP in the drying process.
基金supported by the National key research and development program (2019YFA0607104)National Natural Science Foundation of China (Grant Nos. 41991231, 42275034, 41975076, 42075029, 42075017, and 42075018)the Gansu Provincial Science and Technology Project (22JR5RA405)。
文摘As an important factor that directly affects agricultural production, the social economy, and policy implementation,observed changes in dry/wet conditions have become a matter of widespread concern. However, previous research has mainly focused on the long-term linear changes of dry/wet conditions, while the detection and evolution of the non-linear trends related to dry/wet changes have received less attention. The non-linear trends of the annual aridity index, obtained by the Ensemble Empirical Mode Decomposition(EEMD) method, reveal that changes in dry/wet conditions in China are asymmetric and can be characterized by contrasting features in both time and space in China. Spatially, most areas in western China have experienced transitions from drying to wetting, while opposite changes have occurred in most areas of eastern China. Temporally, the transitions occurred earlier in western China compared to eastern China. Research into the asymmetric spatial characteristics of dry/wet conditions compensates for the inadequacies of previous studies, which focused solely on temporal evolution;at the same time, it remedies the inadequacies of traditional research on linear trends over centennial timescales. Analyzing the non-linear trend also provides for a more comprehensive understanding of the drying/wetting changes in China.
基金supported by the National Natural Science Foundation of China(Grant No.41972265)the Fundamental Research Funds for the Central Universities(Grant No.lzujbky-2021-57)+1 种基金the Gansu Province Science Foundation(Grant No.20JR10RA492)Special thanks to the Environmental Research and Education Foundation for supporting the first author(Y.Tan)through a fellowship for his study at the University of Wisconsin-Madison.
文摘Experiments were conducted to evaluate the healing of drying cracks in air-dried bentonite-sand blocks after hydration and swelling in groundwater,providing justifications to simplify the protection of blocks prior to installation in a high-level radioactive waste repository.Synthetic groundwater was prepared to represent the geochemistry of Beishan groundwater,and was used to hydrate the blocks during the swelling pressure and swelling strain measurements,as Beishan is the most promising site for China's repository.Healing of the surface cracks was recorded by photography,and healing of the internal cracks was visualized by CT images and hydraulic conductivity of air-dried blocks.The results indicate that the maximum swelling pressure and swelling strain are primarily affected by the geochemistry of Beishan groundwater,but not affected by the drying cracks.The maximum swelling pressure and swelling strain of air-dried blocks are comparable to or even higher than the pressure and strain of fresh blocks.The maximum swelling pressure measured in strong(i.e.high ion strength)Beishan groundwater was 44%of the pressure measured in deionized(DI)water,and the maximum swelling strain was reduced to 23%of the strain measured in DI water.Nevertheless,the remained swelling of the blocks hydrated in strong Beishan groundwater was sufficient to heal the surface and internal drying cracks,as demonstrated by the pictures of surface cracks and CT images.The hydraulic conductivity of the air-dried block permeated with strong groundwater was comparable(3.7×higher)to the hydraulic conductivity of the fresh block,indicating the self-healing of drying cracks after hydration and swelling in groundwater.A simplified method of protecting the block with plastic wraps before installation is recommended,since the remained swelling of the block hydrated in Beishan groundwater is sufficient to heal the drying cracks.
基金This work was supported by the National Natural Science Foundation of China(32071943,32272198).
文摘Lysine content is a criterion of the nutritional quality of rice.Understanding the process of lysine biosynthesis in early-flowering superior grain(SG)and late-flowering inferior grain(IG)of rice would advance breeding and cultivation to improve nutritional quality.However,little information is available on differences in lysine anabolism between SG and IG and the underlying mechanism,and whether and how irrigation regimes affect lysine anabolism in these grains.A japonica rice cultivar was grown in the field and two irrigation regimes,continuous flooding(CF)and wetting alternating with partial drying(WAPD),were imposed from heading to the mature stage.Lysine content and activities of key enzymes of lysine biosynthesis,and levels of brassinosteroids(BRs)were lower in the IG than in the SG at the early grainfilling stage but higher at middle and late grain-filling stages.WAPD increased activities of these key enzymes,BR levels,and contents of lysine and total amino acids in IG,but not SG relative to CF.Application of 2,4-epibrassinolide to rice panicles in CF during early grain filling reproduced the effects of WAPD,but neither treatment altered the activities of enzymes responsible for lysine catabolism in either SG or IG.WAPD and elevated BR levels during grain filling increased lysine biosynthesis in IG.Improvement in lysine biosynthesis in rice should focus on IG.
基金the National Natural Science Foundation of China(Grant No.22075146).
文摘Appropriate drying process with optimized controlling of drying parameters plays a vital role in the improvement of the quality and performance of propellant products.However,few research on solvent transport dynamics within NC-based propellants was reported,and its effect on the evolution of mechanical properties was not interpreted yet.This study is conducted to gain a comprehensive understanding of hot-air drying for NC-based propellants and clarify the effect of temperature on solvent transport behavior and further the change of mechanical properties during drying.The drying kinetic curves show the drying time required is decreased but the steady solvent content is increased and the drying rate is obviously increased with the increase of hot-air temperatures,indicating hot-air temperatures have a significant effect on drying kinetics.A modified drying model was established,and results show it is more appropriate to describe solvent transport behavior within NC-based propellants.Moreover,two linear equations were established to exhibit the relationship between solvent content and its effect on the change of tensile properties,and the decrease of residual solvent content causes an obvious increase of tensile strength and tensile modulus of propellant products,indicating its mechanical properties can be partly improved by adjustment of residual solvent content.The outcomes can be used to clarify solvent transport mechanisms and optimize drying process parameters of double-based gun propellants.
基金supported by the National Natural Science Foundation of China(Grant No.:82130113)the National Key R&D Program of China(Program No.:2023YFC3504402)+2 种基金the China Postdoctoral Science Foundation(Grant No.:2021MD703800)the Science Foundation for Youths of Science&Technology Department of Sichuan Province(Grant Nos.:2023NSFSC1775,2022NSFSC1449)the“Xinglin Scholars”Research Promotion Program of Chengdu University of TCM(Grant Nos.:BSH2021009,QJRC2022044).
文摘The dried roots of Aconitum pendulum Busch are the major source of a commonly used Tibetan medicine,namely Tiebangchui(TBC)(Fig.S1).However,raw TBC contains a large amount of high toxic diester-diterpenoid alkaloids(DDAs),and the improper use would cause arrhythmia,irreversible cardiovascular damages,and even death.“Paozhi”,an appropriate processing method,is the essential prerequisite for the safe clinical application of TBC.Water-decocting and sand-frying are commonly used processing methods for toxicity attenuation and efficacy preservation for TBC.
基金financially supported by the HAAFS Science and Technology Innovation Special Project China(2022KJCXZX-LYS-9)the Natural Science Foundation of Hebei Province China(C2021301004)the Key Research and Dvelopment Program of Hebei Province China(20326401D)。
文摘Adjusting agronomic measures to alleviate the kernel position effect in maize is important for ensuring high yields.In order to clarify whether the combined application of organic fertilizer and chemical fertilizer(CAOFCF)can alleviate the kernel position effect of summer maize,field experiments were conducted during the 2019 and 2020 growing seasons,and five treatments were assessed:CF,100%chemical fertilizer;OFCF1,15%organic fertilizer+85%chemical fertilizer;OFCF2,30%organic fertilizer+70%chemical fertilizer;OFCF3,45%organic fertilizer+55%chemical fertilizer;and OFCF4,60%organic fertilizer+40%chemical fertilizer.Compared with the CF treatment,the OFCF1 and OFCF2 treatments significantly alleviated the kernel position effect by increasing the weight ratio of inferior kernels to superior kernels and reducing the weight gap between the superior and inferior kernels.These effects were largely due to the improved filling and starch accumulation of inferior kernels.However,there were no obvious differences in the kernel position effect among plants treated with CF,OFCF3,or OFCF4 in most cases.Leaf area indexes,post-silking photosynthetic rates,and net assimilation rates were higher in plants treated with OFCF1 or OFCF2 than in those treated with CF,reflecting an enhanced photosynthetic capacity and improved postsilking dry matter accumulation(DMA)in the plants treated with OFCF1 or OFCF2.Compared with the CF treatment,the OFCF1 and OFCF2 treatments increased post-silking N uptake by 66.3 and 75.5%,respectively,which was the major factor driving post-silking photosynthetic capacity and DMA.Moreover,the increases in root DMA and zeatin riboside content observed following the OFCF1 and OFCF2 treatments resulted in reduced root senescence,which is associated with an increased post-silking N uptake.Analyses showed that post-silking N uptake,DMA,and grain yield in summer maize were negatively correlated with the kernel position effect.In conclusion,the combined application of 15-30%organic fertilizer and 70-85%chemical fertilizer alleviated the kernel position effect in summer maize by improving post-silking N uptake and DMA.These results provide new insights into how CAOFCF can be used to improve maize productivity.
文摘AIM:To explore ocular surface manifestations of dry eye disease(DED)and its influencing factors in systemic lupus erythematosus(SLE)patients.METHODS:Ophthalmological examinations were conducted in SLE patients(n=43)and controls(n=41),including Ocular Surface Disease Index(OSDI),objective scatter index(OSI),tear meniscus height(TMH),lipid layer thickness(LLT),non-invasive Keratograph tear breakup time(NIKBUT),corneal fluorescein score(CFS),Schirmer I test.DED was diagnosed according to the Tear Film and Ocular Surface Society Dry Eye Workshop II Criteria.SLE patients were further divided into DED group and non-DED group,the disease activity,clinical manifestations and laboratory investigations were compared between the two groups.The disease activity was evaluated by Systemic Lupus Erythematosus Disease Activity Index 2000(SLEDAI-2K).Receiver operative characteristic(ROC)curve and multiplefactor binary logistic regression were performed.RESULTS:SLE patients showed higher OSDI[9.1(2.8-15.9)vs 6.3(2.2-7.5),P=0.035],higher OSI[1.67(1.09-2.60)vs 0.96(0.87-1.60),P=0.001],higher CFS[1(0-2)vs 0(0-1),P=0.001],lower LLT[65(42-100)vs 100(79.5-100),P=0.010],and lower NIKBUT[8.03(4.02-9.73)vs 9.67(5.26-12.71),P=0.030]than controls.The 32.6%of SLE patients had DED,which was higher than 12.2%of healthy controls.DED group showed higher SLEDAI-2K score[9.7±6.1 vs 5.4±3.4,P=0.025],higher anti-cardiolipin antibody(ACL)[8.7(3.5-13.2)vs 3.6(2.0-6.9),P=0.035],and higher proportion of patients with cutaneous eruption[42.9%vs 6.9%,P=0.015]than non-DED group.According to multiple-factor binary logistic regression analysis,the SLEDAI-2K score(OR=1.194,P=0.041)and cutaneous eruption(OR=7.094,P=0.045)could be consider as risk factors for DED in SLE patients.The ROC curve of the combined factors including age,disease duration,SLEDAI-2K score,ACL,and cutaneous eruption was analyzed,with a sensitivity of 0.786,a specificity of 0.793,and an area under curve of 0.820.CONCLUSION:Ocular surface affection is frequent in SLE patients,and patients with high disease activity and cutaneous eruption show increased risk of DED.
文摘The development of microbial-based products requires certain criteria for them to be successfully commercialized. The product must meet the following desirable criteria: effectiveness, contamination free, stability, cost-effectiveness, and a prolonged shelf life. Controlling the drying process is crucial for ensuring the stability and durability of the product. The traditional approach, which involved mechanical and natural drying, led to decreased productivity and quality. The objective of this research endeavour was to achieve a dry process enhancement while preserving the microbial quality of Trichoderma asperellum (M103). The temperature and relative humidity during the drying period were monitored under two conditions: with and without a dehumidifier. The results demonstrate that the dehumidifier increases drying period efficiency by up to 63%.
文摘Monolithic refractory castables comprising a hydraulic bond are still used in a vast majority of cases because of their flexibility and robustness,despite many developments for chemical as well as non-cement castable binders.The drying can however be a challenge,in particular for deflocculated dense castables of the low cement castable range.Many publications have been released on this topic for the last ten years,but they often focused on the drying mechanisms or on the addition of drying aids.This paper presents some experimental results on the effect of the composition on the drying properties,especially on the effect of silicon carbide,used for its high thermal conductivity,and on the matrix system.It also introduces two laboratory tests to study and iteratively improve the drying schedule of a given castable lining.The results show that the spalling resistance and the vapor pressure build-up are significantly influenced by the formulation.It is also shown that the castable properties after drying can be altered if the heating rate is very high.
基金the Coordenacao de Aperfeicoamento de Pessoal de Nivel Superior-Brasil(CAPES)-Finance Code 001.The authors would like to thank the Fundacao de Amparo a Pesquisa do Estado de Sao Paulo-FAPESP(grant number:2021/00251-0).Finally,the authors are also greatly thankful for FIRE support to carry out this work.
文摘Refractories have unique capabilities such as sustaining their shape and properties at extreme conditions such as the combination of high temperatures and thermal shock,contact with molten metals and slags and in some circumstances resistance to erosion from abrasive particles.Given the large processing output of the heavy industries such as the cement and steel ones which both require high temperature processes,the refractories structures span various meters and weight of several tons.As the water removal stage of hydraulic bonded castables in industrial sites takes hours(10-60 h)due to the risk of explosive spalling,efforts to mitigate it are commonly studied.This has provided theoretical understanding of the general aspects of drying and important tools,such as the thermogravimetry analysis(TGA),for the design of refractory compositions with higher explosive spalling resistance.However,the optimization of this process is still far from the industrial reality especially because the actual linings that require the drying are orders of magnitude larger than the samples considered in the laboratory tests.Therefore,this study proposed the analysis of the sample volume effect on the water removal dynamics through TGA of high alumina castables with calcium aluminate cement.Conventionalφ5 cm×5 cm cylindrical samples were assessed in a laboratory scale equipment whereas macro TGA were carried out considering 20 cm×20 cm×20 cm and 30 cm×30 cm×30 cm cubic samples.Additionally,the effect of polymeric fibers was also considered.It was found out that the different thermal gradients within the macro TGA samples resulted in an inflection on the sample’s heating rate and that the mass loss was affected by the volume considered,especially for the composition without additives.These findings highlight the requirement of carefully taking into consideration the different dimensional sizes and thermal gradients in the samples when analyzing and interpreting the laboratory studies,and especially when trying to extrapolate such results to the industrial reality.
文摘Under the current context of climate change, supplementary irrigation may be needed for crop production resilience. We determined the effects of supplementary irrigation on sorghum grain yield in the dry Savannah region of Togo. A two-year trial was conducted in a controlled environment at AREJ, an agro-ecological center in Cinkassé. The plant material was sorghum variety Sorvato 28. The experimental design was a Completely Randomized Block with three replications and three treatments as follows: T0 control plot (rainfed conditions);T1 (supplementary irrigation from flowering to grain filling stage) and T2 (supplementary irrigation from planting to grain filling stage). Two irrigation techniques (furrow and Californian system) were used under each watering treatment. The results showed that irrigation technique significantly affected panicle length with no effect on 1000 grains mass. Panicle length and grain yields varied from 15.59 to 25.71 cm and 0.0 to 2.06 t∙h−1, respectively, with the highest values (25.66 cm and 2.06 t∙h−1, respectively) under the T2 treatment with the California system-based supplementary irrigation. The comparison of results obtained on treatment T0 and T2, shows that supplementary irrigation increased the yields by at least 68.62%. Supplementary irrigation during sowing and growing season (T2) improved sorghum yields in the dry savannahs of Togo, with a better performance of the California irrigation system.
文摘Background: Dry eye and glaucoma are two common pathologies in the elderly, and are very often associated. This association suggests a link between them and between their treatments. Our purpose for this study is to determine the prevalence of dry eye in our glaucoma patients treated with eye drops and deduce the factors associated with it. Patients and Methods: We conducted a cross-sectional, analytical study from October 2022 to September 2023 in the ophthalmology department of Garoua Regional Hospital in glaucoma patients aged over 15 years able to answer the Ocular Surface Disease Index (OSDI) questionnaires and treated with antiglaucoma eye drops for more than 3 months. These patients underwent a complete ophthalmological examination and a tear film break-up time test. Results: A total of 73 patients (146 eyes) were examined. The average age of the patients was 47.2 ± 16.5 years, with a male predominance of 54.8%. The prevalence of dry eye syndrome in our patients according to the OSDI score was 56.2% (95% CI) (44.8;67.6). The prevalence of dry eye syndrome on clinical examination of the BUT in the right eye was 83.7% (95% CI) (75.1;92.1) and 79.4% (70.2;88.7) in the left eye. The duration of antiglaucoma treatment was the factor associated with dry eye syndrome (p < 0.05) in glaucoma patients in our setting. Conclusion: Dry Eye Syndrome is common in glaucoma patients on drops in our setting. Treatment duration of more than 1 year seems to be associated with dry eyes.
文摘This study is an extension of the previous work done with ARS-680 Environmental Chamber. Drying is a complex operation that demands much energy and time. Drying is essentially important for preservation of ginger rhizome. Drying of ginger was modeled, and then the effective diffusion coefficient and activation energy were determined. For this purpose, the experiments were done at six levels of varied temperatures: 10°C, 20°C, 30°C, 40°C, 50°C and 60°C. The values of effective diffusion coefficients obtained in this work for the variously treated ginger rhizomes closely agreed with the average effective diffusion coefficients of other notable authors who determined the drying kinetics and convective heat transfer coefficients of ginger slices.
文摘We set out to model the oven-drying kinetics of a legume known as pigeon pea, harvested in the Bouenza department in the south-west of the Republic of Congo. The drying kinetics of pigeon peas was carried out in an oven under experimental conditions using temperatures of: 50°C, 60°C and 70°C. Seven mathematical models were used to describe pigeon pea drying. During drying, water loss was faster and shorter at 70°C [10.446 g/25 g wet weight (wwb) for 320 min (5.3 h)] compared to 50°C [10.996 g/25 g wet weight (wwb) for 520 min (8.6 h)] and 60°C [10.616 g/25 g wet weight (wwb) for 420 min (7.0 h)] where it was slower and longer. With regard to modeling, and based on the principle of choosing the right model focusing on the high value of R2 and low values of χ2 and RMSE, two models were selected, the Midili model for temperatures of 50°C and 60°C and the Henderson and Pabis model modified for temperature of 70°C showed better results. The R2, χ2 and RMSE values calculated for pigeon pea are 0.99985, 3.93404E-5 and 0.00627;0.9997, 9.245E-5 and 0.00962;0.99996, 1.56332E-5 and 0.00395 respectively at 50°C, 60°C and 70°C.
基金sponsored by the National Natural Science Foundation of China(31461143015,31271641,31471438)the National Key Technology Support Program of China(2014AA10A605,216YFD0300206-4)+1 种基金the Priority Academic Program Development of Jiangsu Higher Education Institutions(PAPD),Chinathe Jiangsu Creation Program for Post-graduation Students,China(KYZZ15_0364)
文摘This study investigated if super rice could better cope with soil water deficit and if it could have better yield performance and water use efficiency (WUE) under alternate wetting and drying (AWD) irrigation than check rice. Two super rice cultivars and two elite check rice cultivars were grown in pots with three soil moisture levels, well watered (WW), moderate water deficit (MWD) and severe water deficit (SWD). Two cultivars, each for super rice and check rice, were grown in field with three irrigation regimes, alternate wetting and moderate drying (AWMD), alternate wetting and severe drying (AWSD) and conventional irrigation (CI). Compared with that under WW, grain yield was significantly decreased under MWD and SWD treatments, with less reduction for super rice than for check rice. Super rice had higher percentage of productive tillers, deeper root distribution, higher root oxidation activity, and greater aboveground biomass production at mid and late growth stages than check rice, especially under WMD and WSD. Compared with CI,AWMD increased, whereasAWSD decreased grain yield, with more increase or less decrease for super rice than for check rice. Both MWD and SWD treatments and eitherAWMD orAWSD regime significantly increased WUE compared with WW treatment or CI regime, with more increase for super rice than for check rice. The results suggest that super rice has a stronger ability to cope with soil water deficit and holds greater promising to increase both grain yield and WUE by adoption of moderate AWD irrigation.
基金supported by the National Key R&D Program of China(2016YFA0202900)the National Natural Science Foundation of China(21622606)+1 种基金Zhejiang Provincial Natural Science Foundation of China(LR18B060001)the Fundamental Research Funds for the Central Universities~~
文摘Supported metal catalysts play a vital role in the chemical industry, and the metal-support interaction is an important property of the catalyst. However, in the traditional impregnation method, it is difficult to obtain sufficient metal-support interactions owing to the mobility of the metal precursor during evaporation drying. Here, freeze drying is applied during impregnation instead of evaporation drying for enhancing the metal-support interactions. 57 Fe ZSM-5 was chosen as a representative catalyst. A quantitative analysis was conducted based on Mossbauer spectroscopy. Compared with traditional evaporation-drying catalyst, freeze-drying catalyst has stronger metal-support interactions. In addition, more iron species are confined in the channel and smaller metal sizes and less diversity are obtained. The compositional change is also proved because of the superior performance of the freeze-drying catalyst during N2O decomposition. This method can be extended to other supported metal catalysts prepared through an impregnation method, which can be used to tune the metal-support interactions and metal sizes.
文摘In kiln drying of softwood timber, external heat and moisture mass transfercoefficients are important in defining boundary temperature and moisture content at the woodsurface. In addition, superheated steam drying of wood is a promising technology but this has notbeen widely accepted commercially, partially due to the lack of understanding of the dryingphenomena occurred during drying. In this work, experimental investigation was performed to quantifythe heat transfer between wood surface and surrounding moist air or superheated steam. In theexperiment, saturated radiata pine sapwood samples were dried using dry-bulb/wet-bulb temperaturesof 60℃/50℃, 90℃/60℃, 120℃/70℃, 140℃/90℃, 160℃/90℃, 140℃/100℃ and 160℃/100℃. The lasttwo schedules were for superheated steam drying as the wet-bulb temperature was set at 100℃. Thecirculation velocity over the board surface was controlled at 4.2m·s^(-1). Two additional runs(90℃/60℃) using air velocities of 2.4 m·s^(-1) and 4.8 m·s^(-1) were performed to check theeffect of the circulation velocity. During drying, sample weight and temperatures at wood surfaceand different depths were continuously measured. Prom these measurements, changes in woodtemperature and moisture content were calculated and external heat-transfer coefficient wasdetermined for both the moist air and the superheated steam drying.
基金Funded by the Key Research and Development Program of Zhejiang Province in 2018(No2018C03033-1)。
文摘We introduced a parameter r_s(the radius of the pores where the meniscus forms),which is composed of two factors,i e,water loss and cumulative pore size distribution(PSD),to provide a better explanation of the influence of superplasticizers(SPs)on early-age drying shrinkage.In our experiments,it is found that the addition of three types of SPs leads to a significant increase in the early-age drying shrinkage of cement paste,and drying shrinkage increases with the dosage of SPs.Based on the results above,we further studied the mechanism of the effects of SPs on the early-age drying shrinkage of cement paste by PSD and water loss,which are two components of r_s.The experimental results indicate that r_s can be a better index for the early-age drying shrinkage of cement-based materials with SPs than a single factor.In addition,the effects of SPs on other factors such as hydration degree and elastic modulus were also investigated and discussed.
文摘TiO_2-CeO_2 nanocomposite particles were prepared with Ce(NO_3)_3·6H_2O and TiCl_4 as precursors by the codeposition method and supercritical fluid drying (SCFD) technology. The particles prepared were characterized by means of XRD, TEM and FTIR. The results show that SCFD can give rise to the direct synthesis of the anatase TiO_2-CeO_2,and the particle size is 6~11 nm under 500 ℃ thermal-treated,smaller than that by common drying (CD). The phase transformation from anatase to rutile is inhibited by supercritical fluid drying technology. The peak of CeO_2 is not observed in XRD patterns,Ce-O band vibration was present in FTIR spectrum,which indicates that CeO_2 is well dispersed on the surface of TiO_2.