Phosphate-manganese, tannic acid and vanadium conversion coatings were proposed as an effective pre-treatment layer between electroless Ni-P coating and AZ91D magnesium alloy substrate to replace the traditional chrom...Phosphate-manganese, tannic acid and vanadium conversion coatings were proposed as an effective pre-treatment layer between electroless Ni-P coating and AZ91D magnesium alloy substrate to replace the traditional chromate plus HF pre-treatment. The electrochemical results show that the chrome-free coatings plus electroless Ni-P coating on the magnesium alloy has the lowest corrosion current density and most positive corrosion potential compared with chromate plus electroless Ni-P coating on the magnesium alloy. These proposed pre-treatment layers on the substrate reduce the corrosion of magnesium during plating process, and reduce the potential difference between the matrix and the second phase. Thus, an electroless Ni-P coating with fine crystalline and dense structure was obtained, with preferential phosphorus content, low porosity, good corrosion-resistance and strengthened adhesion than the chromate plus electroless Ni-P.展开更多
Coagulation-based pre-treatment efficiency of high strength digestate of food waste(HSDFW) anaerobic digestion is negated by organic ligand-catalyzed decomposition of coagulants. In this study, an efficient HSDFW pre-...Coagulation-based pre-treatment efficiency of high strength digestate of food waste(HSDFW) anaerobic digestion is negated by organic ligand-catalyzed decomposition of coagulants. In this study, an efficient HSDFW pre-treatment method, magnetic seeds(MS) coagulation, was employed by using highly stable Keggin Al_(30) nanocluster(PAC_(30)), MS and polyacrylamide(PAM), and its operation was optimized by evaluating the performance of removing turbidity, total suspended solids(TSS), chemical oxygen demand(COD), and total phosphorous(TP) phosphate. Results showed that at the optimum dosage of 4.82 g/L, PAC_(30) demonstrated excellent removals as high as 98.93% ± 0.1% of turbidity, 98.04% ± 0.1% of TSS, 58.28% ± 0.3% of total COD, 99.98% ± 0.01% of TP and 99.50% ± 0.01% of dissolved phosphate, respectively. Apparent molecular weight(AMW) and three-dimensional excitation-emission matrix(3 D-EEM) fluorescence spectroscopy analyses demonstrated more efficient removal of dissolved organic matter(DOM), particularly non-biodegradable and hydrophobic components by PAC_(30) than commercial coagulant. The sedimentation was much improved from 40 min by coagulation/flocculation to about 5 min settling by MS coagulation. The PAC_(30) based magnetic coagulation(MC) presents theoretical guidance on a cost-effective and much less footprint pre-treatment alternative for high strength wastewater.展开更多
Impact of ultrasonication（ULS） and ultrasonication-ozonation（ULS-Ozone） pre-treatment on the anaerobic digestibility of sewage sludge was investigated with semi-continuous anaerobic reactors at solid retention tim...Impact of ultrasonication（ULS） and ultrasonication-ozonation（ULS-Ozone） pre-treatment on the anaerobic digestibility of sewage sludge was investigated with semi-continuous anaerobic reactors at solid retention time（SRT） of 10 and 20 days. The control, ULS and ULS-Ozone reactors produced 256, 309 and 348 m L biogas/g CODfedand the volatile solid（VS） removals were 35.6%, 38.3% and 42.1%, respectively at SRT of 10 days. At SRT of20 days, the biogas yields reached 313, 337 and 393 m L biogas/g CODfedand the VS removal rates were 37.3%, 40.9% and 45.3% in the control, ULS and ULS-Ozone reactors, respectively.ULS-Ozone pre-treatment increased the residual organic amount in the digested sludge.These soluble residual organics were found to contain macromolecules with molecular weights（MW） larger than 500 k Da and smaller polymeric products with MW around 19.4and 7.7 k Da. These compounds were further characterized to be humic acid-like substances with fluorescent spectroscopy analysis.展开更多
The organic matter and two types of disinfection byproduct(DBP) precursors in micropolluted source water were removed using an iron–carbon micro-electrolysis(ICME)combined with up-flow biological aerated filter(UBAF)...The organic matter and two types of disinfection byproduct(DBP) precursors in micropolluted source water were removed using an iron–carbon micro-electrolysis(ICME)combined with up-flow biological aerated filter(UBAF) process. Two pilot-scale experiments(ICME-UBAF and UBAF alone) were used to investigate the effect of the ICME system on the removal of organic matter and DBP precursors. The results showed that ICME pretreatment removed 15.6% of dissolved organic matter(DOM)and significantly improved the removal rate in the subsequent UBAF process. The ICME system removed 31% of trichloromethane(TCM) precursors and 20% of dichloroacetonitrile(DCAN) precursors. The results of measurements of the molecular weight distribution and hydrophilic fractions of DOM and DBP precursors showed that ICME pretreatment played a key role in breaking large-molecular-weight organic matter into low-molecular-weight components, and the hydrophobic fraction into hydrophilic compounds, which was favorable for subsequent biodegradation by UBAF.Three-dimensional fluorescence spectroscopy(3D-EEM) further indicated that the ICME system improved the removal of TCM and DCAN precursors. The biomass analysis indicated the presence of a larger and more diverse microbial community in the ICME-UBAF system than for the UBAF alone. The high-throughput sequencing results revealed that domination of the genera Sphingomonas, Brevundimonas and Sphingorhabdus contributed to the better removal of organic matter and two types of DBP precursors. Also, Nitrosomonas and Pseudomonas were beneficial for ammonia removal.展开更多
AIM: To investigate the effects of selenium in rat retinal ischemia reperfusion(IR) model and compare pretreatment and post-treatment use.METHODS: Selenium pre-treatment group(n =8) was treated with intraperitoneal(i....AIM: To investigate the effects of selenium in rat retinal ischemia reperfusion(IR) model and compare pretreatment and post-treatment use.METHODS: Selenium pre-treatment group(n =8) was treated with intraperitoneal(i.p.) selenium 0.5 mg/kg for7 d and terminated 24 h after the IR injury. Selenium posttreatment group( n = 8) was treated with i. p. selenium0.5 mg/kg for 7d after the IR injury with termination at the end of the 7d period. Sham group(n =8) received i.p.saline injections identical to the selenium volume for 7d with termination 24 h after the IR injury. Control group(n =8) received no intervention. Main outcome measures were retina superoxide dismutase(SOD), glutathione(GSH),total antioxidant status(TAS), malondialdehyde(MDA),DNA fragmentation levels, and immunohistological apoptosis evaluation.RESULTS: Compared to the Sham group, selenium pre-treatment had a statistical difference in all parameters except SOD. Post-treatment selenium also resulted in statistical differences in all parameters except the MDA levels. When comparing selenium groups, the pre-treatment selenium group had a statistically higher success in reduction of markers of cell damage such as MDA and DNA fragmentation. In contrast, the post-selenium treatment group had resulted in statisticallyhigher levels of GSH. Histologically both selenium groups succeeded to limit retinal thickening and apoptosis. Pre-treatment use was statistically more successful in decreasing apoptosis in ganglion cell layer compared to post-treatment use.CONCLUSION: Selenium was successful in retinal protection in IR injuries. Pre-treatment efficacy was superior in terms of prevention of tissue damage and apoptosis.展开更多
Pre-treatment, which supplies a stable, high-quality feed for reverse osmosis （RO） membranes, is a criti- cal step for successful operation in a seawater reverse osmosis plant. In this study, ceramic membrane system...Pre-treatment, which supplies a stable, high-quality feed for reverse osmosis （RO） membranes, is a criti- cal step for successful operation in a seawater reverse osmosis plant. In this study, ceramic membrane systems were employed as pre-treatment for seawater desalination. A laboratory experiment was performed to investigate the effect of the cross-flow velocity on the critical flux and consequently to optimize the permeate flux. Then a pilot test was performed to investigate the long-term performance. The result shows that there is no significant effect of the cross-flow velocity on the critical flux when the cross-flow velocity varies in laminar flow region only or in turbulent flow region only, but the effect is distinct when the cross-flow velocity varies in the transition region. The membrane fouling is slight at the permeate flux of 150 L·m^-2·h^-1 and the system is stable, producing a high-quality feed （the turbidity and silt density index are less than 0.1 NTU and 3.0, respectively） for RO to run for 2922.4 h without chemical cleaning. Thus the ceramic membranes are suitable to filtrate seawater as the pre-treatment for RO.展开更多
Microwave,as a new heat treatment technology,has the characteristics of uniform and fast heating speed.It is an energy-saving technology known for improving oilseed product quality.Its efficiency mainly depends on the...Microwave,as a new heat treatment technology,has the characteristics of uniform and fast heating speed.It is an energy-saving technology known for improving oilseed product quality.Its efficiency mainly depends on the roasting power and time.However,the production of high-quality peanut butter using short-time roasting con-ditions are limited.Herein,we determined an appropriate microwave roasting power and time for peanuts and evaluated its impacts on the quality of peanut butter.Different roasting powers(400 W,800 W and 1200 W)and times(4,4.5,5,and 5.5 min)were preliminarily tested.Among them,800 W at 5 min was the most suitable.The roasting efficiency was further evaluated using color,sensory,bioactive compounds,storage stability,and safety risk factors of peanut butter produced from four peanut cultivars(Silihong,Baisha-1016,Yuanza-9102,and Yuhua-9414).The pre-treated butter obtained from three cultivars(Silihong,Yuanza-9102,and Yuhua-9414)with moisture content between 5%and 7.2%had a similar sensory score(6-7)as the commercial on a 9-point hedonic scale compare to the other.The color of the pre-treated peanut butter varies statistically with the commercial but remained in the recommended range of Hunter L*values of 51-52,respectively,for high initial moisture peanut cultivars.The total polyphenol(35.20-31.59±0.59μmol GAE/g)and tocopherol(19.05±0.35 mg/100 g)content in the butter obtained from three cultivars(Yuahua-9102,Yuhua,and Baisha-1016)and Silihong respectively,were significantly(P<0.05)higher than those in the commercial butter.The induction times of all pre-treated butter(19.80±0.99-7.84±0.07 h)were significantly(P<0.05)longer during storage at accelerated temperature than commercial samples.In addition,no benzo[a]pyrene was found in the pre-treated samples.Collectively,the microwave pretreated peanut butter was superior to the commercial one.These findings provided data support and a reference basis to promote microwave use for peanut butter production.展开更多
A knowledge of the tree-ring stable nitrogen isotope ratio(δ^(15)N)can deepen our understanding of forest ecosystem dynamics by indicating the long-term availability,cycling and sources of nitrogen(N).However,the rad...A knowledge of the tree-ring stable nitrogen isotope ratio(δ^(15)N)can deepen our understanding of forest ecosystem dynamics by indicating the long-term availability,cycling and sources of nitrogen(N).However,the radial mobility of N blurs the interannual variations in the long-term N records.Previous studies of the chemical extraction of tree rings before analysis had produced inconsistent results and it is still unclear whether it is necessary to pre-treat wood samples from specific tree species to remove soluble N compounds before determining theδ^(15)N values.We compared the effects of pre-treatment with organic solvents and hot ultrapure water on the N concentration andδ^(15)N of tree rings from endemic Qinghai spruce(Picea crassifolia)growing in the interior of the central Qilian Mountains,China,during the last 60 a.We assessed the effects of different preparation protocols on the removal of the labile N compounds and investigated the need to pre-treat wood samples before determining theδ^(15)N values of tree rings.Increasing trends of the tree-ring N concentration were consistently observed in both the extracted and unextracted wood samples.The total N removed by extraction with organic solvents was about 17.60%,with a significantly higher amount in the sapwood section(P<0.01).Theδ^(15)N values of tree rings decreased consistently from 1960 to 2019 in both the extracted and unextracted wood samples.Extraction with organic solvents increased theδ^(15)N values markedly by about 5.2‰and reduced the variations in theδ^(15)N series.However,extraction with hot ultrapure water had little effect,with only a slight decrease in theδ^(15)N values of about 0.5‰.Our results showed that the radial pattern in the inter-ring movement of N in Qinghai spruce was not minimized by extraction with either organic solvents or hot ultrapure water.It is unnecessary to conduct hot ultrapure water extraction for the wood samples from Qinghai spruce because of its negligible effect on the removal of the labile N.Theδ^(15)N variation trend of tree rings in the unextracted wood samples was not influenced by the heartwood-sapwood transition zone.We suggest that theδ^(15)N values of the unextracted wood samples of the climate-sensitive Qinghai spruce could be used to explore the ecophysiological dynamics while focusing on the long-term variations.展开更多
Achieving the strength-ductility synergy in Mg alloys is a gigantic challenge,especially in rare-earth-free Mg alloys.In this study,a new Mg-Sn-Zn-Zr alloy with high ultimate tensile strength(~284-326 MPa)without sacr...Achieving the strength-ductility synergy in Mg alloys is a gigantic challenge,especially in rare-earth-free Mg alloys.In this study,a new Mg-Sn-Zn-Zr alloy with high ultimate tensile strength(~284-326 MPa)without sacrificing elongation-to-failure(~22.1-27.6%)was developed by utilizing casting,pre-treatment and hot extrusion.Strong random rather than basal texture is observed both in as-cast and pre-treatment samples.Subsequently,the strong texture is effectively weakened via hot extrusion whilst remaining random.More importantly,after hot extrusion,the grain sizes of as-cast and pre-treatment samples were significantly refined down to about 10μm.Examination of as-extruded microstructures of the alloy reveals that the grain refinement is highly associated with the particle stimulated nucleation(PSN)and continuous/discontinuous dynamic recrystallization(C/DDRX)mechanisms.Moreover,the results suggest that the combination of pre-treatment and hot extrusion not only promotes multiplication of geometrically-necessary dislocations(GNDs)but enhances dynamic precipitation,which boosts the formation of fine and homogenous precipitates.Based on the results of X-ray diffraction(XRD),transmission electron microscope(TEM)and selected area electron diffraction(SAED),the precipitates are Mg_(2)Sn phases.Furthermore,the main orientation relationship identified by high resolution TEM(HRTEM)between Mg_(2)Sn phases andα-Mg matrix could be described as(111)Mg_(2)Snor(220)Mg_(2)Sn∥(0001)Mgwith a coherent interface.The refined grains size,ultra-fine precipitates and high density of GNDs would substantially contribute to the enhancement of the strength and the corresponding contributions are calculated to be~183-185 MPa,~30.9-38 MPa and~14.2-31.7 MPa,respectively.Besides,texture weakening or randomizing,grain refinement and coherent interfaces are mainly responsible for the high ductility.The current study can provide beneficial insights into the development of high-performance rare-earth-free Mg alloys with favorable microstructure via a combination of casting,pre-treatment and hot extrusion processing.展开更多
Detailed experimental investigations were carried out for microwave pre-treatment of high ash Indian coal at high power level(900 W) in microwave oven. The microwave exposure times were fixed at60 s and 120 s. A rheol...Detailed experimental investigations were carried out for microwave pre-treatment of high ash Indian coal at high power level(900 W) in microwave oven. The microwave exposure times were fixed at60 s and 120 s. A rheology characteristic for microwave pre-treatment of coal-water slurry(CWS) was performed in an online Bohlin viscometer. The non-Newtonian character of the slurry follows the rheological model of Ostwald de Waele. The values of n and k vary from 0.31 to 0.64 and 0.19 to 0.81 Pa·sn,respectively. This paper presents an artificial neural network(ANN) model to predict the effects of operational parameters on apparent viscosity of CWS. A 4-2-1 topology with Levenberg-Marquardt training algorithm(trainlm) was selected as the controlled ANN. Mean squared error(MSE) of 0.002 and coefficient of multiple determinations(R^2) of 0.99 were obtained for the outperforming model. The promising values of correlation coefficient further confirm the robustness and satisfactory performance of the proposed ANN model.展开更多
BACKGROUND During cirrhosis,the liver is impaired and unable to synthesize and clear thrombopoietin properly.At the same time,the spleen assumes the function of hemofiltration and storage due to liver dysfunction,resu...BACKGROUND During cirrhosis,the liver is impaired and unable to synthesize and clear thrombopoietin properly.At the same time,the spleen assumes the function of hemofiltration and storage due to liver dysfunction,resulting in hypersplenism and excessive removal of platelets in the spleen,further reducing platelet count.When liver function is decompensated in cirrhotic patients,the decrease of thrombopoietin(TPO)synthesis is the main reason for the decrease of new platelet production.This change of TPO leads to thrombocytopenia and bleeding tendency in cirrhotic patients with hypersplenism.AIM To investigate the clinical efficacy of recombinant human TPO(rhTPO)in the treatment of perioperative thrombocytopenia during liver transplantation in cirrhotic mice with hypersplenism.METHODS C57BL/6J mice and TPO receptor-deficient mice were used to establish models of cirrhosis with hypersplenism.Subsequently,these mice underwent orthotopic liver transplantation(OLT).The mice in the experimental group were given rhTPO treatment for 3 consecutive days before surgery and 5 consecutive days after surgery,while the mice in the control group received the same dose of saline at the same frequency.Differences in liver function and platelet counts were determined between the experimental and control groups.Enzyme-linked immunosorbent assay was used to assess the expression of TPO and TPO receptor(c-Mpl)in the blood.RESULTS Preoperative administration of rhTPO significantly improved peri-OLT thrombocytopenia in mice with cirrhosis and hypersplenism.Blocking the expression of TPO receptors exacerbated peri-OLT thrombocytopenia.The concentration of TPO decreased while the concentration of c-Mpl increased in compensation in the mouse model of cirrhosis with hypersplenism.TPO pre-treatment significantly increased the postoperative TPO concentration in mice,which in turn led to a decrease in the c-Mpl concentration.TPO pre-treatment also significantly enhanced the Janus kinase(Jak)/signal transducers and activators of transcription pathway protein expressions in bone marrow stem cells of the C57BL/6J mice.Moreover,the administration of TPO,both before and after surgery,regulated the levels of biochemical indicators,such as alanine aminotransferase,alkaline phosphatase,and aspartate aminotransferase in the C57BL/6J mice.CONCLUSION Pre-treatment with TPO not only exhibited therapeutic effects on perioperative thrombocytopenia in the mice with cirrhosis and hypersplenism,who underwent liver transplantation but also significantly enhanced the perioperative liver function.展开更多
The effect of pre-treatment of dewatered sludge using different nitrite concentrations and p H for microbial fuel cell(MFC) application was investigated. The results show that the addition of nitrite was feasible to i...The effect of pre-treatment of dewatered sludge using different nitrite concentrations and p H for microbial fuel cell(MFC) application was investigated. The results show that the addition of nitrite was feasible to increase the solubilization rate of the sludge and may reduce mass transfer limitation at the anode. This helped the MFC to reach higher voltage and to generate more power. The higher free nitrous acid(FNA) concentration under the acidic condition helped to increase sludge solubilization. However, under an alkaline condition, during which the FNA concentration was relatively low, the solubilization of the sludge was higher. The highest voltage and power density produced was 390 mV and 153 mW/m^2, respectively, with the addition of nitrite at 100 mg-N/L and pH 9. Furthermore,it was found that elevated levels of FNA could inhibit electrogenic bacteria thus reducing power generation.展开更多
Samples of Bi-2223/Ag tapes fabricated with powders contained different lead oxide compounds were annealed at a temperature lower than the formation temperature of Bi-2223 phase before traditional heat treatment,which...Samples of Bi-2223/Ag tapes fabricated with powders contained different lead oxide compounds were annealed at a temperature lower than the formation temperature of Bi-2223 phase before traditional heat treatment,which was called pretreatment.In pre-treatment stage,samples were heat treated at 780℃in 8.5%O2,and the dwelling time is different.Experimental results show that pre-treatment had different influence on the formation and size of the Bi-2223 grains for tapes fabricated with powders contained different lead oxide compounds.For tapes contained both Ca2PbO4 and the 3321 phase,the decomposition of the 3321 phase enhanced the growth of Bi-2212 grains during pre-treatment process,which promoted the formation of Bi-2223 phase and enhanced the superconducting properties of Bi-2223/Ag tapes.展开更多
Buried interfacial voids have always been a notorious phenomenon observed in the fabrication of lead perovskite films. The existence of interfacial voids at the buried interface will capture the carrier, suppress carr...Buried interfacial voids have always been a notorious phenomenon observed in the fabrication of lead perovskite films. The existence of interfacial voids at the buried interface will capture the carrier, suppress carrier transport efficiencies, and affect the stability of photovoltaic devices. However, the impact of these buried interfacial voids on tin perovskites, a promising avenue for advancing lead-free photovoltaics, has been largely overlooked. Here, we utilize an innovative weakly polar solvent pretreatment strategy(WPSPS) to mitigate buried interfacial voids of tin perovskites. Our investigation reveals the presence of numerous voids in tin perovskites during annealing, attributed to trapped dimethyl sulfoxide(DMSO) used in film formation. The WPSPS method facilitates accelerated DMSO evaporation, effectively reducing residual DMSO. Interestingly, the WPSPS shifts the energy level of PEDOT:PSS downward, making it more aligned with the perovskite. This alignment enhances the efficiency of charge carrier transport. As the result, tin perovskite film quality is significantly improved,achieving a maximum power conversion efficiency approaching 12% with only an 8.3% efficiency loss after 1700 h of stability tests, which compares well with the state-of-the-art stability of tin-based perovskite solar cells.展开更多
The purpose of this work was to study the potential to enhance biogas production from pulp and paper mill sludge by the use of thermal pre-treatment in combination with chemical pre-treatment. Biogas from waste is a r...The purpose of this work was to study the potential to enhance biogas production from pulp and paper mill sludge by the use of thermal pre-treatment in combination with chemical pre-treatment. Biogas from waste is a renewable fuel with very low emissions during combustion. To further reduce the use of fossil fuels, more biogas substrates are necessary. Pulp and paper mill sludge is a large untapped reservoir of potential biogas. Pulp and paper mill sludge was collected from a mill that produces both pulp and paper and has a modified waste activated sludge system as part of its wastewater treatment. Pre-treatments were chosen heat （70 ~C or 140℃） combined with either acid （pH 2 or pH 4） or base （pH 9 or pH 11, obtained with Ca（OH）2 or NaOH）. Biogas potential was tested by anaerobic digestion batch assays under mesophilic conditions. All pre-treatments were tested in six replicates. Biogas volume was measured with a gas-tight syringe and methane concentration was measured with a gas chromatograph. The methane yield from sludge subjected to thermal pre-treatment at 70℃ did not differ from the untreated sludge, but thermal pre-treatment at 140℃ had a positive effect. Within the 70℃ thermal pre-treatment group, the pH 2 acid was the most successful chemical pre-treatment, and Ca（OH）2 pH 9 had the least effect with no measurable improvement in methane yield. For the 140 ℃ thermal pre-treatment group, acid and NaOH impacted methane production negatively, while the Ca（OH）2-treated sludge did not differ from sludge with no chemical pre-treatment. In conclusion, thermal pre-treatment at 70℃ showed no effect, whereas, pre-treatment at 140℃ improved methane yield with 170%, and for this sludge additional, chemical pre-treatments are unnecessary.展开更多
Purpose This study aimed to optimize the pre-treatment process for electroless nickel-phosphorus plating in the Einstein Probe project,addressing technical challenges encountered with 6061 aluminum alloy substrates to...Purpose This study aimed to optimize the pre-treatment process for electroless nickel-phosphorus plating in the Einstein Probe project,addressing technical challenges encountered with 6061 aluminum alloy substrates to enhance coating quality and operational efficiency.Methods Verification experiments were conducted using 6061 aluminum alloy sheets as substitutes for large aluminum mandrels.The effects of surface roughness,rinsing methods,and the necessity of acid pickling were systematically evaluated.The samples were characterized by scanning electron microscopy,atomic force microscopy,and energy-dispersive X-ray spectroscopy to analyze surface morphology and elemental composition.Results and Conclusion Excessive surface roughness should be avoided,with a roughness below 338 nm ensuring uniform coatings.Flowing water rinsing after each step was critical to prevent contamination from residual solutions,whereas stagnant water immersion proved inadequate.Acid pickling was determined to be non-essential,as it had minimal impact on coating quality.The zinc layer formed during immersion exhibited weak adhesion and should be rinsed gently to avoid detachment.These findings offer valuable insights for pre-treatment process refinement in the Einstein Probe project and related applications.展开更多
Chinese jujube is delicious and nourishing fruit.However,fresh Chinese jujube is liable to rot and drying is a necessary process.Traditional drying is a time-consuming task due to the thick cuticle of Chinese jujube.T...Chinese jujube is delicious and nourishing fruit.However,fresh Chinese jujube is liable to rot and drying is a necessary process.Traditional drying is a time-consuming task due to the thick cuticle of Chinese jujube.To improve its drying efficiency,fresh Chinese jujube was pretreated with nine different methods prior to hot-air drying.Among these methods,dipping in 2%ethyl oleate plus 5%K_(2)CO_(3) for 10 min(alkaline emulsion of ethyl oleate,AEEO)was recommended for its time-saving effect,which was found more significant at lower drying temperatures.The beneficial effect was considered based on its cuticle destruction by AEEO pre-treatment.In the meantime,the drying process was divided into three stages;each of them obeyed the first order reaction kinetics.Activation energies for the first,second and third stages of control over jujube drying were 41.45 kJ/mol,35.24 kJ/mol and 49.52 kJ/mol,and reduced by 20.9%,22.1%and 29.0%,respectively,after AEEO pre-treatment,and the drying process was well predicted by Midilli et al.model.In view of browning during drying at higher temperatures,AEEO pretreated jujube was suggested to be dried at 60°C.This finding was considered to be helpful to the industrial drying of Chinese jujube.展开更多
Amorphous/crystalline silicon heterojunctions（a-Si：H/c-Si SHJ） were prepared by plasma-enhanced chemical vapor deposition（PECVD）.The influence of the initial transient state of the plasma and the hydrogen pre-tre...Amorphous/crystalline silicon heterojunctions（a-Si：H/c-Si SHJ） were prepared by plasma-enhanced chemical vapor deposition（PECVD）.The influence of the initial transient state of the plasma and the hydrogen pre-treatment on the interfacial properties of the heteroj unctions was studied.Experimental results indicate that： （1） The instability of plasma in the initial stage will damage the surface of c-Si.Using a shutter to shield the substrate for 100 s from the starting discharge can prevent the influence of the instable plasma process on the Si surface and also the interface between a-Si and c-Si.（2） The effect of hydrogen pre-treatment on interfacial passivation is constrained by the extent of hydrogen plasma bombardment and the optimal time for hydrogen pre-treatment is about 60 s.展开更多
基金Project(50871046)supported by the National Natural Science Foundation of ChinaProject(2010CB631001)supported by the National Basic Research Program of China+1 种基金Project supported by the Program for Changjiang Scholars and Innovative Research Team inUniversity,ChinaIndo-China cultural exchange scholarship program by the Ministry of Human Resource Department(MHRD,India)and Ministry of Education(MOE,China)
文摘Phosphate-manganese, tannic acid and vanadium conversion coatings were proposed as an effective pre-treatment layer between electroless Ni-P coating and AZ91D magnesium alloy substrate to replace the traditional chromate plus HF pre-treatment. The electrochemical results show that the chrome-free coatings plus electroless Ni-P coating on the magnesium alloy has the lowest corrosion current density and most positive corrosion potential compared with chromate plus electroless Ni-P coating on the magnesium alloy. These proposed pre-treatment layers on the substrate reduce the corrosion of magnesium during plating process, and reduce the potential difference between the matrix and the second phase. Thus, an electroless Ni-P coating with fine crystalline and dense structure was obtained, with preferential phosphorus content, low porosity, good corrosion-resistance and strengthened adhesion than the chromate plus electroless Ni-P.
基金supported by the National Key Research and Development Program of China (No. 2018YFD1100600)the Program of China-Sri Lanka Joint Center for Water Technology Research and Demonstrationthe Chinese Government Scholarship Program (CSC No. 2018SLJ023250)。
文摘Coagulation-based pre-treatment efficiency of high strength digestate of food waste(HSDFW) anaerobic digestion is negated by organic ligand-catalyzed decomposition of coagulants. In this study, an efficient HSDFW pre-treatment method, magnetic seeds(MS) coagulation, was employed by using highly stable Keggin Al_(30) nanocluster(PAC_(30)), MS and polyacrylamide(PAM), and its operation was optimized by evaluating the performance of removing turbidity, total suspended solids(TSS), chemical oxygen demand(COD), and total phosphorous(TP) phosphate. Results showed that at the optimum dosage of 4.82 g/L, PAC_(30) demonstrated excellent removals as high as 98.93% ± 0.1% of turbidity, 98.04% ± 0.1% of TSS, 58.28% ± 0.3% of total COD, 99.98% ± 0.01% of TP and 99.50% ± 0.01% of dissolved phosphate, respectively. Apparent molecular weight(AMW) and three-dimensional excitation-emission matrix(3 D-EEM) fluorescence spectroscopy analyses demonstrated more efficient removal of dissolved organic matter(DOM), particularly non-biodegradable and hydrophobic components by PAC_(30) than commercial coagulant. The sedimentation was much improved from 40 min by coagulation/flocculation to about 5 min settling by MS coagulation. The PAC_(30) based magnetic coagulation(MC) presents theoretical guidance on a cost-effective and much less footprint pre-treatment alternative for high strength wastewater.
文摘Impact of ultrasonication（ULS） and ultrasonication-ozonation（ULS-Ozone） pre-treatment on the anaerobic digestibility of sewage sludge was investigated with semi-continuous anaerobic reactors at solid retention time（SRT） of 10 and 20 days. The control, ULS and ULS-Ozone reactors produced 256, 309 and 348 m L biogas/g CODfedand the volatile solid（VS） removals were 35.6%, 38.3% and 42.1%, respectively at SRT of 10 days. At SRT of20 days, the biogas yields reached 313, 337 and 393 m L biogas/g CODfedand the VS removal rates were 37.3%, 40.9% and 45.3% in the control, ULS and ULS-Ozone reactors, respectively.ULS-Ozone pre-treatment increased the residual organic amount in the digested sludge.These soluble residual organics were found to contain macromolecules with molecular weights（MW） larger than 500 k Da and smaller polymeric products with MW around 19.4and 7.7 k Da. These compounds were further characterized to be humic acid-like substances with fluorescent spectroscopy analysis.
基金supported by the National Natural Science Foundation of China (No. 51778208)the Major Science and Technology Program for Water Pollution Control and Treatment (No. 2017ZX07201002)the Qing Lan Project, and the Priority Academic Program Development of Jiangsu Higher Education Institutions
文摘The organic matter and two types of disinfection byproduct(DBP) precursors in micropolluted source water were removed using an iron–carbon micro-electrolysis(ICME)combined with up-flow biological aerated filter(UBAF) process. Two pilot-scale experiments(ICME-UBAF and UBAF alone) were used to investigate the effect of the ICME system on the removal of organic matter and DBP precursors. The results showed that ICME pretreatment removed 15.6% of dissolved organic matter(DOM)and significantly improved the removal rate in the subsequent UBAF process. The ICME system removed 31% of trichloromethane(TCM) precursors and 20% of dichloroacetonitrile(DCAN) precursors. The results of measurements of the molecular weight distribution and hydrophilic fractions of DOM and DBP precursors showed that ICME pretreatment played a key role in breaking large-molecular-weight organic matter into low-molecular-weight components, and the hydrophobic fraction into hydrophilic compounds, which was favorable for subsequent biodegradation by UBAF.Three-dimensional fluorescence spectroscopy(3D-EEM) further indicated that the ICME system improved the removal of TCM and DCAN precursors. The biomass analysis indicated the presence of a larger and more diverse microbial community in the ICME-UBAF system than for the UBAF alone. The high-throughput sequencing results revealed that domination of the genera Sphingomonas, Brevundimonas and Sphingorhabdus contributed to the better removal of organic matter and two types of DBP precursors. Also, Nitrosomonas and Pseudomonas were beneficial for ammonia removal.
文摘AIM: To investigate the effects of selenium in rat retinal ischemia reperfusion(IR) model and compare pretreatment and post-treatment use.METHODS: Selenium pre-treatment group(n =8) was treated with intraperitoneal(i.p.) selenium 0.5 mg/kg for7 d and terminated 24 h after the IR injury. Selenium posttreatment group( n = 8) was treated with i. p. selenium0.5 mg/kg for 7d after the IR injury with termination at the end of the 7d period. Sham group(n =8) received i.p.saline injections identical to the selenium volume for 7d with termination 24 h after the IR injury. Control group(n =8) received no intervention. Main outcome measures were retina superoxide dismutase(SOD), glutathione(GSH),total antioxidant status(TAS), malondialdehyde(MDA),DNA fragmentation levels, and immunohistological apoptosis evaluation.RESULTS: Compared to the Sham group, selenium pre-treatment had a statistical difference in all parameters except SOD. Post-treatment selenium also resulted in statistical differences in all parameters except the MDA levels. When comparing selenium groups, the pre-treatment selenium group had a statistically higher success in reduction of markers of cell damage such as MDA and DNA fragmentation. In contrast, the post-selenium treatment group had resulted in statisticallyhigher levels of GSH. Histologically both selenium groups succeeded to limit retinal thickening and apoptosis. Pre-treatment use was statistically more successful in decreasing apoptosis in ganglion cell layer compared to post-treatment use.CONCLUSION: Selenium was successful in retinal protection in IR injuries. Pre-treatment efficacy was superior in terms of prevention of tissue damage and apoptosis.
基金Supported by the National High Technology Research and Development of China (2007AA030303)
文摘Pre-treatment, which supplies a stable, high-quality feed for reverse osmosis （RO） membranes, is a criti- cal step for successful operation in a seawater reverse osmosis plant. In this study, ceramic membrane systems were employed as pre-treatment for seawater desalination. A laboratory experiment was performed to investigate the effect of the cross-flow velocity on the critical flux and consequently to optimize the permeate flux. Then a pilot test was performed to investigate the long-term performance. The result shows that there is no significant effect of the cross-flow velocity on the critical flux when the cross-flow velocity varies in laminar flow region only or in turbulent flow region only, but the effect is distinct when the cross-flow velocity varies in the transition region. The membrane fouling is slight at the permeate flux of 150 L·m^-2·h^-1 and the system is stable, producing a high-quality feed （the turbidity and silt density index are less than 0.1 NTU and 3.0, respectively） for RO to run for 2922.4 h without chemical cleaning. Thus the ceramic membranes are suitable to filtrate seawater as the pre-treatment for RO.
基金Key Research Projects of Hubei Province(2020BBA045)the Agricultural Science and Technology Innovation Project of the Chinese Academy of Agricultural Sciences(CAAS-ASTIP-2016-OCRI)。
文摘Microwave,as a new heat treatment technology,has the characteristics of uniform and fast heating speed.It is an energy-saving technology known for improving oilseed product quality.Its efficiency mainly depends on the roasting power and time.However,the production of high-quality peanut butter using short-time roasting con-ditions are limited.Herein,we determined an appropriate microwave roasting power and time for peanuts and evaluated its impacts on the quality of peanut butter.Different roasting powers(400 W,800 W and 1200 W)and times(4,4.5,5,and 5.5 min)were preliminarily tested.Among them,800 W at 5 min was the most suitable.The roasting efficiency was further evaluated using color,sensory,bioactive compounds,storage stability,and safety risk factors of peanut butter produced from four peanut cultivars(Silihong,Baisha-1016,Yuanza-9102,and Yuhua-9414).The pre-treated butter obtained from three cultivars(Silihong,Yuanza-9102,and Yuhua-9414)with moisture content between 5%and 7.2%had a similar sensory score(6-7)as the commercial on a 9-point hedonic scale compare to the other.The color of the pre-treated peanut butter varies statistically with the commercial but remained in the recommended range of Hunter L*values of 51-52,respectively,for high initial moisture peanut cultivars.The total polyphenol(35.20-31.59±0.59μmol GAE/g)and tocopherol(19.05±0.35 mg/100 g)content in the butter obtained from three cultivars(Yuahua-9102,Yuhua,and Baisha-1016)and Silihong respectively,were significantly(P<0.05)higher than those in the commercial butter.The induction times of all pre-treated butter(19.80±0.99-7.84±0.07 h)were significantly(P<0.05)longer during storage at accelerated temperature than commercial samples.In addition,no benzo[a]pyrene was found in the pre-treated samples.Collectively,the microwave pretreated peanut butter was superior to the commercial one.These findings provided data support and a reference basis to promote microwave use for peanut butter production.
基金supported by the National Natural Science Foundation of China (41971104)the Open Foundation of the State Key Laboratory of Loess and Quaternary Geology,Institute of Earth Environment+1 种基金Chinese Academy of Sciences (CASSKLLQG1817)the Qilian Mountain National Park Research Center (Qinghai)(GKQ2019-01)。
文摘A knowledge of the tree-ring stable nitrogen isotope ratio(δ^(15)N)can deepen our understanding of forest ecosystem dynamics by indicating the long-term availability,cycling and sources of nitrogen(N).However,the radial mobility of N blurs the interannual variations in the long-term N records.Previous studies of the chemical extraction of tree rings before analysis had produced inconsistent results and it is still unclear whether it is necessary to pre-treat wood samples from specific tree species to remove soluble N compounds before determining theδ^(15)N values.We compared the effects of pre-treatment with organic solvents and hot ultrapure water on the N concentration andδ^(15)N of tree rings from endemic Qinghai spruce(Picea crassifolia)growing in the interior of the central Qilian Mountains,China,during the last 60 a.We assessed the effects of different preparation protocols on the removal of the labile N compounds and investigated the need to pre-treat wood samples before determining theδ^(15)N values of tree rings.Increasing trends of the tree-ring N concentration were consistently observed in both the extracted and unextracted wood samples.The total N removed by extraction with organic solvents was about 17.60%,with a significantly higher amount in the sapwood section(P<0.01).Theδ^(15)N values of tree rings decreased consistently from 1960 to 2019 in both the extracted and unextracted wood samples.Extraction with organic solvents increased theδ^(15)N values markedly by about 5.2‰and reduced the variations in theδ^(15)N series.However,extraction with hot ultrapure water had little effect,with only a slight decrease in theδ^(15)N values of about 0.5‰.Our results showed that the radial pattern in the inter-ring movement of N in Qinghai spruce was not minimized by extraction with either organic solvents or hot ultrapure water.It is unnecessary to conduct hot ultrapure water extraction for the wood samples from Qinghai spruce because of its negligible effect on the removal of the labile N.Theδ^(15)N variation trend of tree rings in the unextracted wood samples was not influenced by the heartwood-sapwood transition zone.We suggest that theδ^(15)N values of the unextracted wood samples of the climate-sensitive Qinghai spruce could be used to explore the ecophysiological dynamics while focusing on the long-term variations.
基金National Natural Science Foundation of China(No.12162023)The Key Talent Projects of Gansu Province,Gansu Basic Research Innovation Group Project(No.23JRRA757)Incubation Program of Excellent Doctoral Dissertation-Lanzhou University of Technology。
文摘Achieving the strength-ductility synergy in Mg alloys is a gigantic challenge,especially in rare-earth-free Mg alloys.In this study,a new Mg-Sn-Zn-Zr alloy with high ultimate tensile strength(~284-326 MPa)without sacrificing elongation-to-failure(~22.1-27.6%)was developed by utilizing casting,pre-treatment and hot extrusion.Strong random rather than basal texture is observed both in as-cast and pre-treatment samples.Subsequently,the strong texture is effectively weakened via hot extrusion whilst remaining random.More importantly,after hot extrusion,the grain sizes of as-cast and pre-treatment samples were significantly refined down to about 10μm.Examination of as-extruded microstructures of the alloy reveals that the grain refinement is highly associated with the particle stimulated nucleation(PSN)and continuous/discontinuous dynamic recrystallization(C/DDRX)mechanisms.Moreover,the results suggest that the combination of pre-treatment and hot extrusion not only promotes multiplication of geometrically-necessary dislocations(GNDs)but enhances dynamic precipitation,which boosts the formation of fine and homogenous precipitates.Based on the results of X-ray diffraction(XRD),transmission electron microscope(TEM)and selected area electron diffraction(SAED),the precipitates are Mg_(2)Sn phases.Furthermore,the main orientation relationship identified by high resolution TEM(HRTEM)between Mg_(2)Sn phases andα-Mg matrix could be described as(111)Mg_(2)Snor(220)Mg_(2)Sn∥(0001)Mgwith a coherent interface.The refined grains size,ultra-fine precipitates and high density of GNDs would substantially contribute to the enhancement of the strength and the corresponding contributions are calculated to be~183-185 MPa,~30.9-38 MPa and~14.2-31.7 MPa,respectively.Besides,texture weakening or randomizing,grain refinement and coherent interfaces are mainly responsible for the high ductility.The current study can provide beneficial insights into the development of high-performance rare-earth-free Mg alloys with favorable microstructure via a combination of casting,pre-treatment and hot extrusion processing.
基金the sponsor CSIR (Council of Scientific and Industrial Research), New Delhi for their financial grant to carry out the present research work
文摘Detailed experimental investigations were carried out for microwave pre-treatment of high ash Indian coal at high power level(900 W) in microwave oven. The microwave exposure times were fixed at60 s and 120 s. A rheology characteristic for microwave pre-treatment of coal-water slurry(CWS) was performed in an online Bohlin viscometer. The non-Newtonian character of the slurry follows the rheological model of Ostwald de Waele. The values of n and k vary from 0.31 to 0.64 and 0.19 to 0.81 Pa·sn,respectively. This paper presents an artificial neural network(ANN) model to predict the effects of operational parameters on apparent viscosity of CWS. A 4-2-1 topology with Levenberg-Marquardt training algorithm(trainlm) was selected as the controlled ANN. Mean squared error(MSE) of 0.002 and coefficient of multiple determinations(R^2) of 0.99 were obtained for the outperforming model. The promising values of correlation coefficient further confirm the robustness and satisfactory performance of the proposed ANN model.
基金All procedures involving animals were reviewed and approved by the Tianjin Tiancheng New Drug Evaluation Co.,Ltd(Approval No.2023041701).
文摘BACKGROUND During cirrhosis,the liver is impaired and unable to synthesize and clear thrombopoietin properly.At the same time,the spleen assumes the function of hemofiltration and storage due to liver dysfunction,resulting in hypersplenism and excessive removal of platelets in the spleen,further reducing platelet count.When liver function is decompensated in cirrhotic patients,the decrease of thrombopoietin(TPO)synthesis is the main reason for the decrease of new platelet production.This change of TPO leads to thrombocytopenia and bleeding tendency in cirrhotic patients with hypersplenism.AIM To investigate the clinical efficacy of recombinant human TPO(rhTPO)in the treatment of perioperative thrombocytopenia during liver transplantation in cirrhotic mice with hypersplenism.METHODS C57BL/6J mice and TPO receptor-deficient mice were used to establish models of cirrhosis with hypersplenism.Subsequently,these mice underwent orthotopic liver transplantation(OLT).The mice in the experimental group were given rhTPO treatment for 3 consecutive days before surgery and 5 consecutive days after surgery,while the mice in the control group received the same dose of saline at the same frequency.Differences in liver function and platelet counts were determined between the experimental and control groups.Enzyme-linked immunosorbent assay was used to assess the expression of TPO and TPO receptor(c-Mpl)in the blood.RESULTS Preoperative administration of rhTPO significantly improved peri-OLT thrombocytopenia in mice with cirrhosis and hypersplenism.Blocking the expression of TPO receptors exacerbated peri-OLT thrombocytopenia.The concentration of TPO decreased while the concentration of c-Mpl increased in compensation in the mouse model of cirrhosis with hypersplenism.TPO pre-treatment significantly increased the postoperative TPO concentration in mice,which in turn led to a decrease in the c-Mpl concentration.TPO pre-treatment also significantly enhanced the Janus kinase(Jak)/signal transducers and activators of transcription pathway protein expressions in bone marrow stem cells of the C57BL/6J mice.Moreover,the administration of TPO,both before and after surgery,regulated the levels of biochemical indicators,such as alanine aminotransferase,alkaline phosphatase,and aspartate aminotransferase in the C57BL/6J mice.CONCLUSION Pre-treatment with TPO not only exhibited therapeutic effects on perioperative thrombocytopenia in the mice with cirrhosis and hypersplenism,who underwent liver transplantation but also significantly enhanced the perioperative liver function.
基金funded by Universiti Sains Malaysia via Research University Grant(RUI)scheme(No.1001/PJKIMIA/814267)Bridging Grant scheme(No.304.PJKIMIA.6316120)the Ministry of Higher Education Malaysia for providing scholarship(MyBrain)
文摘The effect of pre-treatment of dewatered sludge using different nitrite concentrations and p H for microbial fuel cell(MFC) application was investigated. The results show that the addition of nitrite was feasible to increase the solubilization rate of the sludge and may reduce mass transfer limitation at the anode. This helped the MFC to reach higher voltage and to generate more power. The higher free nitrous acid(FNA) concentration under the acidic condition helped to increase sludge solubilization. However, under an alkaline condition, during which the FNA concentration was relatively low, the solubilization of the sludge was higher. The highest voltage and power density produced was 390 mV and 153 mW/m^2, respectively, with the addition of nitrite at 100 mg-N/L and pH 9. Furthermore,it was found that elevated levels of FNA could inhibit electrogenic bacteria thus reducing power generation.
基金National High Technology Research and Development ("863") Program (2009AA03Z202)
文摘Samples of Bi-2223/Ag tapes fabricated with powders contained different lead oxide compounds were annealed at a temperature lower than the formation temperature of Bi-2223 phase before traditional heat treatment,which was called pretreatment.In pre-treatment stage,samples were heat treated at 780℃in 8.5%O2,and the dwelling time is different.Experimental results show that pre-treatment had different influence on the formation and size of the Bi-2223 grains for tapes fabricated with powders contained different lead oxide compounds.For tapes contained both Ca2PbO4 and the 3321 phase,the decomposition of the 3321 phase enhanced the growth of Bi-2212 grains during pre-treatment process,which promoted the formation of Bi-2223 phase and enhanced the superconducting properties of Bi-2223/Ag tapes.
基金National Natural Science Foundation of China (62274094, 62175117)Natural Science Foundation of Jiangsu Higher Education Institutions (22KJB510011)+1 种基金Key Lab of Modern Optical Technologies of Education Ministry of China, Soochow University (KJS2260)Huali Talents Program of Nanjing University of Posts and Telecommunications。
文摘Buried interfacial voids have always been a notorious phenomenon observed in the fabrication of lead perovskite films. The existence of interfacial voids at the buried interface will capture the carrier, suppress carrier transport efficiencies, and affect the stability of photovoltaic devices. However, the impact of these buried interfacial voids on tin perovskites, a promising avenue for advancing lead-free photovoltaics, has been largely overlooked. Here, we utilize an innovative weakly polar solvent pretreatment strategy(WPSPS) to mitigate buried interfacial voids of tin perovskites. Our investigation reveals the presence of numerous voids in tin perovskites during annealing, attributed to trapped dimethyl sulfoxide(DMSO) used in film formation. The WPSPS method facilitates accelerated DMSO evaporation, effectively reducing residual DMSO. Interestingly, the WPSPS shifts the energy level of PEDOT:PSS downward, making it more aligned with the perovskite. This alignment enhances the efficiency of charge carrier transport. As the result, tin perovskite film quality is significantly improved,achieving a maximum power conversion efficiency approaching 12% with only an 8.3% efficiency loss after 1700 h of stability tests, which compares well with the state-of-the-art stability of tin-based perovskite solar cells.
文摘The purpose of this work was to study the potential to enhance biogas production from pulp and paper mill sludge by the use of thermal pre-treatment in combination with chemical pre-treatment. Biogas from waste is a renewable fuel with very low emissions during combustion. To further reduce the use of fossil fuels, more biogas substrates are necessary. Pulp and paper mill sludge is a large untapped reservoir of potential biogas. Pulp and paper mill sludge was collected from a mill that produces both pulp and paper and has a modified waste activated sludge system as part of its wastewater treatment. Pre-treatments were chosen heat （70 ~C or 140℃） combined with either acid （pH 2 or pH 4） or base （pH 9 or pH 11, obtained with Ca（OH）2 or NaOH）. Biogas potential was tested by anaerobic digestion batch assays under mesophilic conditions. All pre-treatments were tested in six replicates. Biogas volume was measured with a gas-tight syringe and methane concentration was measured with a gas chromatograph. The methane yield from sludge subjected to thermal pre-treatment at 70℃ did not differ from the untreated sludge, but thermal pre-treatment at 140℃ had a positive effect. Within the 70℃ thermal pre-treatment group, the pH 2 acid was the most successful chemical pre-treatment, and Ca（OH）2 pH 9 had the least effect with no measurable improvement in methane yield. For the 140 ℃ thermal pre-treatment group, acid and NaOH impacted methane production negatively, while the Ca（OH）2-treated sludge did not differ from sludge with no chemical pre-treatment. In conclusion, thermal pre-treatment at 70℃ showed no effect, whereas, pre-treatment at 140℃ improved methane yield with 170%, and for this sludge additional, chemical pre-treatments are unnecessary.
基金supported by the National Natural Science Foundation of China(Grant Nos.42327802 and 22479035).
文摘Purpose This study aimed to optimize the pre-treatment process for electroless nickel-phosphorus plating in the Einstein Probe project,addressing technical challenges encountered with 6061 aluminum alloy substrates to enhance coating quality and operational efficiency.Methods Verification experiments were conducted using 6061 aluminum alloy sheets as substitutes for large aluminum mandrels.The effects of surface roughness,rinsing methods,and the necessity of acid pickling were systematically evaluated.The samples were characterized by scanning electron microscopy,atomic force microscopy,and energy-dispersive X-ray spectroscopy to analyze surface morphology and elemental composition.Results and Conclusion Excessive surface roughness should be avoided,with a roughness below 338 nm ensuring uniform coatings.Flowing water rinsing after each step was critical to prevent contamination from residual solutions,whereas stagnant water immersion proved inadequate.Acid pickling was determined to be non-essential,as it had minimal impact on coating quality.The zinc layer formed during immersion exhibited weak adhesion and should be rinsed gently to avoid detachment.These findings offer valuable insights for pre-treatment process refinement in the Einstein Probe project and related applications.
基金This work was financially supported by National Natural Science Foundation of China(No.81072984).
文摘Chinese jujube is delicious and nourishing fruit.However,fresh Chinese jujube is liable to rot and drying is a necessary process.Traditional drying is a time-consuming task due to the thick cuticle of Chinese jujube.To improve its drying efficiency,fresh Chinese jujube was pretreated with nine different methods prior to hot-air drying.Among these methods,dipping in 2%ethyl oleate plus 5%K_(2)CO_(3) for 10 min(alkaline emulsion of ethyl oleate,AEEO)was recommended for its time-saving effect,which was found more significant at lower drying temperatures.The beneficial effect was considered based on its cuticle destruction by AEEO pre-treatment.In the meantime,the drying process was divided into three stages;each of them obeyed the first order reaction kinetics.Activation energies for the first,second and third stages of control over jujube drying were 41.45 kJ/mol,35.24 kJ/mol and 49.52 kJ/mol,and reduced by 20.9%,22.1%and 29.0%,respectively,after AEEO pre-treatment,and the drying process was well predicted by Midilli et al.model.In view of browning during drying at higher temperatures,AEEO pretreated jujube was suggested to be dried at 60°C.This finding was considered to be helpful to the industrial drying of Chinese jujube.
基金Project supported by the National Key Basic Research Program of China(No.2011CBA00705)the Knowledge Innovation Project of the Chinese Academy of Sciences(No.KGCX2-YW-351).
文摘Amorphous/crystalline silicon heterojunctions（a-Si：H/c-Si SHJ） were prepared by plasma-enhanced chemical vapor deposition（PECVD）.The influence of the initial transient state of the plasma and the hydrogen pre-treatment on the interfacial properties of the heteroj unctions was studied.Experimental results indicate that： （1） The instability of plasma in the initial stage will damage the surface of c-Si.Using a shutter to shield the substrate for 100 s from the starting discharge can prevent the influence of the instable plasma process on the Si surface and also the interface between a-Si and c-Si.（2） The effect of hydrogen pre-treatment on interfacial passivation is constrained by the extent of hydrogen plasma bombardment and the optimal time for hydrogen pre-treatment is about 60 s.
