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1.
《Ceramics International》2020,46(4):4526-4531
To investigate tribological behavior of graphene reinforced chemically bonded ceramic coatings at different temperatures, tribological tests at room temperature, 200 °C and 500 °C were carried out. Results show that the fracture toughness and the hardness of the coating are improved with the introduction of graphene. Besides, the friction coefficient of the coating decreases with the addition of graphene at the room temperature and 200 °C. The coating without graphene achieves the similar friction coefficient at all temperatures. However, the coating with graphene achieves the lowest friction coefficient at 200 °C, and achieves the highest at 500 °C. In addition, the wear rate of the coating decreases with the increase of graphene. Besides, the wear rate at 200 °C is almost similar with that at room temperature. In contrast, the wear rate at 500 °C is much larger than those at room temperature and 200 °C. The mechanisms for graphene to decrease the friction coefficient and improve the wear resistance of chemically bonded ceramic coatings at evaluated temperatures are clarified.  相似文献   

2.
Signaling mediated by cytokines and chemokines is involved in glaucoma-associated neuroinflammation and in the damage of retinal ganglion cells (RGCs). Using multiplexed immunoassay and immunohistochemical techniques in a glaucoma mouse model at different time points after ocular hypertension (OHT), we analyzed (i) the expression of pro-inflammatory cytokines, anti-inflammatory cytokines, BDNF, VEGF, and fractalkine; and (ii) the number of Brn3a+ RGCs. In OHT eyes, there was an upregulation of (i) IFN-γ at days 3, 5, and 15; (ii) IL-4 at days 1, 3, 5, and 7 and IL-10 at days 3 and 5 (coinciding with downregulation of IL1-β at days 1, 5, and 7); (iii) IL-6 at days 1, 3, and 5; (iv) fractalkine and VEGF at day 1; and (v) BDNF at days 1, 3, 7, and 15. In contralateral eyes, there were (i) an upregulation of IL-1β at days 1 and 3 and a downregulation at day 7, coinciding with the downregulation of IL4 at days 3 and 5 and the upregulation at day 7; (ii) an upregulation of IL-6 at days 1, 5, and 7 and a downregulation at 15 days; (iii) an upregulation of IL-10 at days 3 and 7; and (iv) an upregulation of IL-17 at day 15. In OHT eyes, there was a reduction in the Brn3a+ RGCs number at days 3, 5, 7, and 15. OHT changes cytokine levels in both OHT and contralateral eyes at different time points after OHT induction, confirming the immune system involvement in glaucomatous neurodegeneration.  相似文献   

3.
0~20℃养护下硅酸盐水泥水化时钙矾石的生成及转变   总被引:2,自引:0,他引:2  
王培铭  徐玲琳  张国防 《硅酸盐学报》2012,40(5):646-647,648,649,650
采用X射线衍射仪及核磁共振仪研究了0、5、10、20℃硅酸盐水泥水化产物钙矾石的生成及转变。结果表明:硅酸盐水泥水化1d至180d,4种养护温度下钙矾石生成量皆先增大后减小,但该规律随养护温度不同而不同:在10℃和20℃养护时,钙钒石生成量在水化3 d时达到最大,0℃和5℃养护时,水化28d时才达到最大;而从水化龄期来看,钙矾石生成量在水化1d时20℃养护时最高(10.2%),水化3d时10℃养护时最高(12.1%),3~180 d时0℃时最高;此外,低温养护显著延迟了钙矾石向单硫型水化硫铝酸钙转变。  相似文献   

4.
锦纶66浸胶帘子布生产中的张力与控制   总被引:2,自引:0,他引:2  
分析了帘子布生产中张力的作用及各区段的张力情况。张力应根据生产品种及浸胶帘子布的内在质量要求来选择,一般张力设定依据为拉伸区张力是干燥区张力的1倍,定型区张力是拉伸区张力的0.65倍。同时应控制好各区段的温度,降低拉伸应力使锦纶66帘子布拉伸均匀,提高帘子布的物理性能。  相似文献   

5.
The effects of pH and NaCl concentration on protein solubility, emulsification, and foamability of sesame protein concentrate from dehulled seeds were investigated. The protein content of the concentrate was 70.7%. Protein solubility, emulsion, and foaming capacities varied with pH and ionic strength. Protein solubility, which was least at pH 4, (2.1%) ranged from 6.6% at pH 2 to 13.1% at pH 10. The solubility increased with increase in ionic strength, ranging from 9.8% at 0.0 M to 16.1% at 1.0 M concentration. The emulsion capacity ranged from 6.2 mL oil/g sample at pH 2 to 19.4 mL oil/g sample at pH 10. The emulsion capacity increased from 11.5 mL oil/g sample at 0.0 M to 20.9 mL oil/g sample at 1.0 M salt concentration. Stability of the emulsion increased with increase in NaCl concentration, ranging from 42% at 0.0 M concentration to 70% at 1.0 M concentration, but 0.5 M NaCl produced the most stable foam after 120 min of whipping while the least stable was at 1.0 M.  相似文献   

6.
Electrochemical waste water treatment: Electrooxidation of acetaminophen   总被引:2,自引:0,他引:2  
Oxidation of acetaminophen at boron-doped diamond (BDD) and at Ti/SnO2 anodes in a plug-flow divided electrochemical reactor led to electrochemical combustion, whereas at Ti/IrO2 benzoquinone was the exclusive product except at very long electrolysis times. The difference is explicable in terms of the different mechanisms of oxidation: direct oxidation at the anode for Ti/IrO2 vs. indirect oxidation involving electrogenerated hydroxyl radicals at BDD and Ti/SnO2. At BDD, at which the efficiency of degradation of acetaminophen was greatest, the rate of electrolysis at constant concentration was linearly dependent on the current, and at constant current linearly dependent on the concentration. Current efficiencies for mineralization up to 26% were achieved without optimization of the cell design.  相似文献   

7.
水煤浆气化炉内飞灰的形成机理   总被引:2,自引:1,他引:1       下载免费PDF全文
基于实验室规模的多喷嘴对置式水煤浆气化炉,利用SEM、马尔文激光粒度仪和XRD表征气化炉内飞灰的粒径分布和组成,并分析了气化炉内飞灰的形成机理。结果表明,喷嘴平面处飞灰与气化炉出口处飞灰的粒径分布及化学组成存在显著差异,不同气化阶段飞灰的形成机理也不同。气化燃烧阶段飞灰的形成机理为部分固定碳燃烧和外在矿物转化,而在焦炭气化反应阶段,飞灰的形成机理为焦炭破碎和内在矿物释放及转化。  相似文献   

8.
凌有道  吕满庚 《精细化工》2008,25(6):545-550
在5种不同温度下聚合交联,制备了一系列温度和pH双重敏感性聚(N-异丙基丙烯酰胺-co-衣康酸)水凝胶。实验发现,15、25℃得到的凝胶是透明的,45、55℃得到的凝胶是白色不透明的,而在相转变温度附近(35℃)得到的凝胶则是半透明的。FTIR测定表明,它们具有相似的化学组成和结构。SEM观察证实,它们具有不同的表面形态。测定了不同温度和pH下达到平衡时水凝胶的溶胀比,考察了水凝胶在水和强酸性溶液中的去溶胀动力学。结果表明,与15℃或25℃制备的水凝胶相比,45℃和55℃制备的水凝胶的性能有显著提高:(1)溶胀比大为增加。15℃或25℃制备的水凝胶在25℃时溶胀比分别为65.3和68.1,而45℃和55℃制备的水凝胶此时溶胀比分别高达105.7和110.1;(2)45℃和55℃制备的水凝胶在极端环境下对温度的变化仍具有较快的响应速率。例如在温度为60℃,pH=1.67的强酸条件下,45℃和55℃制备的水凝胶在60 min内皆可失去95%的水,而15℃或25℃制备的水凝胶在120 min内只能失去42%左右的水。  相似文献   

9.
碳酸钾生产中吹脱除氨新工艺实验研究   总被引:1,自引:1,他引:0  
在离子交换法生产碳酸钾的基础上,将原有蒸发除氨工艺改为真空加热吹脱除氨工艺.进行了常压加热除氨、真空加热除氨、常压加热吹脱除氨和真空加热吹脱除氨4种工艺方法的实验研究和比较.结果表明,在实验条件下离子交换液的温度、蒸氨时间、气相压力和吹脱气量等对铵离子的分解率有很大影响.真空加热吹脱除氨效果显著.  相似文献   

10.
In-situ transmission electron microscopy (TEM) with ion irradiation has been used to study the damage microstructure evolution of He ion irradiated 4-H SiC at nuclear fusion relevant temperatures. The SiC samples were irradiated with 20?keV He ions at 25, 400, 800 and 1200?°C to a dose of 5.0 displacements per atom (DPA). At 25?°C, the material fully amorphises at 1.5 DPA and no He bubble nucleation occurs up to the doses studied. At 400 and 800?°C, He bubble nucleation occurs and the material remains crystalline. Bubble nucleation occurs at 2.0?DPA at 400?°C but occurs at only 0.5?DPA at 1200?°C. This is attributed the He atoms de-trapping from vacancies and migrating interstitially to larger He-vacancy clusters at higher temperatures, leading to faster nucleation of observable He bubbles. Helium platelets form at an irradiation temperature of 1200?°C at 0.5?DPA showing a preference for nucleation between the {0001} basal planes.  相似文献   

11.
Certain functional properties of sesame seed flour were obtained after oil extraction from dehulled seed meal was investigated. The protein content in the flour was 69.7% and the least gelation concentration was 6.0%. Water and oil absorption capacities at room temperature (31 ± 2°C) were 2.3 g H2O/g sample and 3.0 g oil/g sample, respectively. The values were higher at 100°C. The emulsification capacity, which was more stable at alkaline conditions, ranged from 25.0 mL oil/g sample at pH 4 to 66.0 mL oil/g sample at pH 10. The foaming capacity was more stable at pH 4 but lower (205.0%). The highest foaming capacity (315.0%) was at pH 2 whereas at pH 10 it was 310.0%. Protein solubility, which was least at pH 4, ranged from 7.9% at pH 2 to 14.2% at pH 10. The viscosity of the flour dispersion ranged from 2.5 cps at 1% concentration to 7.0 cps at 10% concentration. The findings show that sesame flour could impart desirable characteristics when incorporated into products such as ice cream, frozen dessert, sausages, baked food and confections.  相似文献   

12.
目的观察在不同温度保存条件下噬菌体展示的1型糖尿病疫苗种子的稳定性。方法将噬菌体展示的1型糖尿病疫苗种子样品分为两组,一组添加等体积的80%甘油,另一组不添加甘油,分别于不同温度条件下存放不同时间后取样,用噬斑法检测滴度。结果在37℃和25℃条件下保存,噬菌体疫苗种子滴度下降较快,在4℃和-20℃条件下保存噬菌体疫苗种子滴度下降相对较慢;37℃、25℃及4℃条件下保存,添加甘油并无明显的保护作用,而在-20℃条件下保存,添加甘油有明显的保护作用。结论噬菌体展示的1型糖尿病疫苗种子可在4℃条件下短期保存,-20℃条件下长期保存,并可添加甘油作为保护剂。  相似文献   

13.
研制了一种单组分无溶剂,使用方便的糊状耐高温双马来酰亚胺胶黏剂,该胶黏剂用双烯丙基双酚A和乙烯基液体丁腈橡胶做增韧剂。当端乙烯基液体丁腈橡胶用量为8%时,胶黏剂25℃剪切强度为23.8MPa,300℃剪切强度为7.6MPa,剥离强度为1.6N/mm,胶黏剂在耐水1000h后,25℃剪切强度为23.6MPa,300%剪切强度为7.4MPa。胶黏剂在300℃老化100h后,25℃剪切强12.6MPa,300℃剪切强度为7.5MPa。  相似文献   

14.
exo-Brevicomin (E), frontalin (F), and myrcene (M) were released at two rates 10-fold apart with verbenone at four rates 10-fold apart, and without verbenone in plots with one trap on a vertical cylinder at the pheromone source and one trap on each of four cylinders 5 m away. Catch of the western pine beetleDendroctonus brevicomis decreased with increasing levels of verbenone at both release rates of EFM, but not all differences in catch were statistically significant. Significantly more beetles were caught at the high rate of EFM than at the low rate, combining all rates of verbenone. The percent of total beetles caught at the center trap tended to decrease with increasing rates of verbenone, but the only statistically significant differences were at the low rate of EFM.Coleoptera: Scolytidae.  相似文献   

15.
无机高分子复合絮凝剂PFSS中硅的形态分析   总被引:1,自引:0,他引:1       下载免费PDF全文
郑怀礼  王白雪  张占梅  谢礼国  蔚阳 《化工学报》2007,58(11):2937-2942
应用Si-Mo逐时络合比色形态表征法, 对无机高分子复合絮凝剂聚硅硫酸铁(PFSS)中硅的形态进行了研究,包括SiO2反应速率特征及其标准工作曲线,不同pH值条件下聚硅酸(PSi)的形态分布特征,不同pH值时PFSS与PSi中硅的形态特征比较。结果表明:不同pH值的PFSS中,硅的聚合形态熟化一定时间后,分布规律有所不同。pH值为1.46和1.70时,PFSS中硅酸的中聚体含量比pH值为0.64时的高,而pH值为0.64时,PFSS中硅酸的高聚态、凝胶态含量明显高于pH值为1.46和1.70的相应含量。同时,pH值为1.46和1.70的PFSS比pH值为0.64的PFSS有更好的絮凝性能和稳定性。由此可知,PFSS中聚硅酸的优势形态是其中聚体。  相似文献   

16.
徐啸  朱晓兵  周集体  李任征 《化工学报》2015,66(Z2):332-341
由于受环境污染的影响,淡水资源的供给问题日趋严峻,供给方式的新技术探索是有效解决问题的重要途径,尤其是海水淡化的相关技术。利用实验室自制的垂直电场电泳装置,研究模拟海水的脱盐效果(以氯离子为研究对象)。考察了氯离子初始浓度、停留时间和电压3个因素分别对脱盐率、能量效率(单位电功能量的正极区迁移的氯离子质量)和分布比率的影响。出水分为4个区域,正极区、负极区、中间区和两极邻近区,其中中间区代表模拟海水淡化的目标收集区。结果表明,随着入水口处的氯离子初始浓度的增加,电泳装置出水口的中间区的脱盐率降低,能量效率逐渐升高,中间区、负极区和两极邻近区的分布比率增大,而正极区的分布比率减小。随着停留时间的增加,中间区脱盐率明显升高,高达69.5%,能量效率逐渐降低,中间区和负极区的分布比率减小,而正极区和两极邻近区的分布比率增加。随着电压升高,中间区的脱盐率逐渐升高,最高达13.9%,能量效率逐渐降低,正极区的分布比率逐渐增大,而负极区和两极邻近区的分布比率逐渐减小,中间区分布比率呈先上升后降低趋势。  相似文献   

17.
刘学军 《中国塑料》2022,36(3):134-139
研究了单轴转动的圆筒形滚塑模具在加热阶段其内表面传热系数与模具转速之间的关系,首先为滚塑工艺的加热阶段建立一个简化的传热模型,然后通过MATLAB软件求解了该模型的微分方程,从而将实验测得的加热时间转换成模具的内表面传热系数.在模具静止和转速较高的工况时,模内粉料的状态是确定且不随时间改变的,因此可通过FLUENT软件...  相似文献   

18.
特种氯丁橡胶热氧老化研究   总被引:1,自引:0,他引:1  
通过对特种氯丁橡胶在热空气中进行加速老化,比较了其老化前后性能的变化,得出了该橡胶的性能变化与老化时间的函数关系,并建立了100%定伸应力、拉伸强度、断裂伸长率、强韧度、撕裂强度与邵尔A硬度之间的关联关系。结果表明:在整个老化期间,100%定伸应力、硬度逐渐增加;拉伸强度、断裂伸长率、强韧度、撕裂强度逐渐降低;机械性能与硬度呈线性关系。  相似文献   

19.
《化学工程》1995,23(4):65-67
测定了温度范围在0~45℃,压力达到84.6×10 ̄5pa时,N_2,H_2,Ar在正辛醇中的75点高压气体溶解度数据,并提出一个由高压实验数据回归常压溶解度的方法。  相似文献   

20.
A pot experiment was conducted in a greenhouse to assess the effect of rate and time of N application on yield and N uptake of wetland rice grown on a Rangsit acid sulfate soil (Sulfic Tropaquepts). Response of rice at N rates of 800, 1600 and 2400 mg N/pot (5 kg of soil) was compared between urea and ammonium sulfate when applied at two times: (i) full-rate basal at transplanting and (ii) one half at transplanting and one half at the PI stage. In addition, labelled15N sources were applied either at transplanting or at the PI stage to determine the nitrogen balance sheet in the soil/plant system.No significant difference in grain and straw yields between urea and ammonium sulfate at low rate was observed. At the higher N rates, urea produced higher yields than did ammonium sulfate regardless of timing. The highest yields were obtained when urea at the high N rate was applied either in a single dose or a split dose while lowest yields were observed particularly when ammonium sulfate at the same rate was applied. Split application of N fertilizer was shown to be no better than a single basal application. The occurrence of nutritional disorder, a symptom likely reflected by high concentration of Fe (II) in combination with soluble Al, was induced with high rate of ammonium sulfate.In terms of fertilizer N recovery by using15N-labelling, ammonium sulfate was more efficient than urea when both were applied at transplanting. In contrast, application at the PI stage resulted in higher utilization of urea than of ammonium sulfate. The recovery of labelled N in the soil was higher with urea than with ammonium sulfate when the two sources were applied at transplanting, while the opposite result was obtained when the same fertilizers were applied at the PI stage. The losses from urea and ammonium sulfate were not different when these fertilizers were applied at transplanting but loss from urea was higher than that from ammonium sulfate when both were applied at the PI stage.  相似文献   

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