共查询到19条相似文献，搜索用时 203 毫秒
1.
The performance of Al-alloy anode in 4 mol/L KOH with and without stannate and o-aminophenol at 25℃ and 55℃ was studied by hydrogen collection, potentiodynamic polarization and electrochemical impedance spectrum, o-aminophenol acts as a perfect inhibitor because of its adsorbability and forming chelate complex at its optimum concentration of 0.4 mol/L. Stannate enhances the inhibition of o-aminophenol and improves the activity of Al-alloy because of its reduction to tin. There is synergetic effect of stannate with o-aminophenol on the behavior of Al-alloy, and the inhibitive efficiency at 55℃ is better than that at 25 ℃. 相似文献
2.
两相Mg-Ni合金的电化学吸放氢行为 总被引：1，自引：0，他引：1
刘卫红 《上海大学学报(英文版)》2002,6(4):349-352
The electrochemical performance of double phase Mg-Ni alloy was characterized at 25℃ and 70℃，in order to evaluate briefly its utility as negative electrode materials in nickel-metal hydride batteries.The results show that the electrochemical capacity of double phase Mg-Ni alloy is rarely low at 25℃,but increased rapidly when the temperature is enhanced,and the double phase Mg-Ni alloy has its maximum capacity at the first discharge cycle,but the capacity degrades rapidly with cycling number. 相似文献
3.
In order to clarify the equilibrium components in the hydrolysis solution of boron trifluoride(BF_3-H_2O),the BF_3-H_2O was prepared by mixing BF_3-CH_3OH with large amount of water,in which the stoichiometric concentration of BF_3 is less than 0.1 mol/L.Two ionic equilibrium models were proposed to simulate the hydrolysis equilibrium of BF_3 and tested by special acid-base titration technique.The most accurate ion equilibrium constants were determined.The model,which was assumed to have no HF,was proved to be more representative for the real system and used to simulate the hydrolysis equilibrium of BF_3.The simulation suggested that H~+,BF_4~-,BF_3OH~- and H_3BO_3 were the main species in the dilute hydrolysis solution,while BF_2(OH)_2~- and F~- were insignificant species whose concentrations were both in the order of 10~(-4) mol/L magnitude,and BF(OH)_3~- could be omitted because its concentration almost equaled zero.Meanwhile,the equilibrium constant of the overall ionic reaction at 25℃ was obtained as 161.6. 相似文献
4.
A method was proposed to determine boron trifluoride in boron trifluoride complex using fluoride ion selective electrode(ISE). Hydroxide was chosen to mask aluminum for the determination of 0.01—0.1 mol/L of fluoride. The simulation indicated that the permissible aluminum masked at a certain p H value was limited and hardly related to F-concentration and boric acid. It is better to control p H value below 11.5 and the aluminum concentration within 0.025 mol/L to minimize the interference of hydroxide to the fluoride ISE. The decomposition conditions of boron trifluoride by aluminum chloride were investigated. It is found that the F-detection ratio will approach 1.0 if the Al/F molar ratio is 0.3—0.7 and aluminum concentration is no more than 0.02 mol/L when heated at 80 ℃ for 10 min. In one word, hydroxide is quite fit to mask aluminum for samples which contain high content of fluoride and aluminum and the BF3 content can be successfully determined by this method. 相似文献
5.
Appropriate addition of CuO/V2O5 and the reduction of the granularity of the raw materials particle decrease the sintering temperature ofNiZn ferrite from 1200℃ to 930 ℃. Furthermore, the magnetic properties of the NiZn ferrite prepared at low temperature of 930℃ is superior to that of the NiZn ferrite prepared by sintering at high temperature of 1200 ℃ because the microstructure of the NiZn ferrite sintered at 930℃ is more uniform and compact than that of the NiZn ferrite sintered at 1200℃. The high permeability of 1700 and relative loss coefficient tanδ/μi of 9.0-10^-6 at 100 kHz was achieved in the (Ni0.17Zn0.63Cu0.20)Fe 1.915O4 ferrite. 相似文献
6.
Appropriate addition of CuO/V2O5 and the reduction of the granularity of the raw materials particle decrease the sintering temperature ofNiZn ferrite from 1200 ℃ to 930 ℃. Furthermore, the magnetic properties of the NiZn ferrite prepared at low temperature of 930 ℃ is superior to that of the NiZn ferrite prepared by sintering at high temperature of 1200 ℃ because the microstructure of the NiZn ferrite sintered at 930 ℃ is more uniform and compact than that of the NiZn ferrite sintered at 1200 ℃.The high permeability of 1700 and relative loss coefficient tanδ//μi of 9.0×10-6 at 100 kHz was achieved in the (Ni0.17Zn0.63Cu0.20)Fe1.915O4 ferrite. 相似文献
7.
Apple is one of the favorite fruits among the western people and there are many idioms with the word. Apple is popular among people,not only because of its sweet flavor and rich nutrient（营养); people love it mainly because of its shape. Red and round apple is the symbol of happiness and good luck. 相似文献
8.
Aquatic toxicity of di （2-eihylhexyl） phthalate to duckweeds 总被引：1，自引：0，他引：1
This study is concerned with the effects of di （2-ethylhexyl） phthalate （DEHP） on two kinds of duckweeds （Spirodela polyrhiza and Lemna minor）.The results indicate that DEHP has aquatic toxicity to Spirodela polyrhiza at 0.4 mg/L and to Lemna minor at over 0.1 mg/L by changing their physiologic-biochemical characteristics.The contents of duckweed chlorophyll and soluble protein decrease with increasing DEHP concentration after 7 d of exposure.DEHP shows the stimulating role in catalase （CAT） and superoxide dismutase （SOD） systems at relative low levels.At 0.01 mg/L and 0.005 mg/L,SOD activities of Spirodela polyrhiza and Lemna minor reach their peak values respectively,while CAT activity reaches its maximum value at 0.05 mg/L and 0.01 mg/L.When DEHP levels are too high,the protection enzyme system would be destroyed and plant growth is inhibited.The analysis of malondialdehyde （MDA） and Fourier transform infrared spectroscopy manifest that DEHP could affect the tested duckweeds by destroying its cell membranes,and Spirodela polyrhiza is more resistant to DEHP exposure than Lemna minor. 相似文献
9.
Habib M Hussain I Fang WH Rajput ZI Yang ZZ Irshad H 《Journal of Zhejiang University. Science. B》2006,7(4):320-323
In this experiment conducted to study the inactivation dynamics of infectious bursal disease virus （IBDV） by binary ethylenimine （BEI） in comparison with formalin, IBDV was isolated from the bursa of infected chickens and its confirmation was done by agar gel precipitation test. Viral suspensions were subjected to inactivation with BEI and formalin for pre-set time in- tervals. BEI was employed at concentrations of 0.001 and 0.002 mol/L while formalin was used at 0.1% and 0.2%. Sampling was done at 6, 12, 24, 36 and 48 h of incubation and samples were tested for their inactivation status in 9-day-old embryonated eggs and 3-week-old broiler chickens. IBDV was completely inactivated by 0.001 and 0.002 mol/L BEI after 36 h of incubation at 37℃, whereas formalin at 0. 1% and 0.2% concentrations inactivated IBDV in 24 h. 相似文献
10.
Zou LK Wang HN Pan X Tian GB Xie ZW Wu Q Chen H Xie T Yang ZR 《Journal of Zhejiang University. Science. B》2008,9(7):536-545
The phyAm gene encoding acid phytase and optimized neutral phytase phyCs gene were inserted into expression vector pPIC9K in correct orientation and transformed into Pichiapastoris in order to expand the pH profile of phytase and decrease the cost of production. The fusion phytase phyAm-phyCs gene was successfully overexpressed in P. pastoris as an active and ex-tracellular phytase. The yield of total extracellular fusion phytase activity is (25.4±0.53) U/ml at the flask scale and (159.1±2.92) U/ml for high cell-density fermentation, respectively. Purified fusion phytase exhibits an optimal temperature at 55 ℃ and an optimal pH at 5.5～6.0 and its relative activity remains at a relatively high level of above 70% in the range of pH 2.0 to 7.0. About 51% to 63% of its original activity remains after incubation at 75 ℃ to 95 ℃ for 10 min. Due to heavy glycosylation, the expressed fusion phytase shows a broad and diffuse band in SDS-PAGE (sodium dodecyl sulfate-polyacrylamide gel electrophoresis). After deglycosylation by endoglycosidase H (EndoHf), the enzyme has an apparent molecular size of 95 kDa. The characterization of the fusion phytase was compared with those of phyCs and phyAm. 相似文献
11.
建立并优化虎耳草ISSR-PCR反应体系和扩增程序,为探讨虎耳草种质资源遗传多样性奠定基础.采用正交设计方法和单因子试验,研究TaqDNA聚合酶、dNTP、Mg2+、引物、模板DNA、延伸时间及循环次数对PCR扩增的影响.结果表明:虎耳草ISSR-PCR的最佳反应体系为:在25μL的反应体系中含模板DNA 35ng,Mg2+1.25mmo/lL、dNTP 380μmo/lL、引物1.2μmo/lL、Taq DNA聚合酶1.5U.反应程序为:95℃预变性5min;94℃变性1min,50℃(据不同引物的退火温度)退火70s,72℃延伸1.5min,40个循环;72℃延伸10min,4℃保存.经过11份虎耳草种质检验,证明该体系稳定可靠,可用于虎耳草种质资源遗传多样性分析及居群鉴别的研究. 相似文献
12.
以乙二胺、三羟甲基丙烷三丙烯酸酯和二乙醇胺或三羟甲基氨基甲烷为原料,合成了水溶性树枝状聚（胺-酯）.讨论了树枝状聚（胺-酯）用量、离心时间及溶液pH值对于Cr3＋去除率的影响.实验结果表明,25℃时,当pH=9.22,以3000 r/min的转速离心13 min,用20 mL PAE（NH2）8（c=0.01 mol/L）溶液处理10 mL CrCl3（c=0.1 mol/L）溶液时,Cr3＋的去除率最高,为81.72%;25℃时,当pH=8.48,以3000 r/min的转速离心10 min,用20 mL PAE（OH）16（c=0.01 mol/L）溶液处理10 mL CrCl3（c=0.1 mol/L）溶液时,Cr3＋的去除率最高,为90.85%;25℃时,当pH=7.67,以3000 r/min的转速离心7 min,用20 mL PAE（OH）24（c=0.01 mol/L）溶液处理10 mL CrCl3（c=0.1 mol/L）溶液时,Cr3＋的去除率最高,为95.17%. 相似文献
13.
不同处理条件对洋葱鳞茎表皮细胞骨架形态影响的研究 总被引：1，自引：0，他引：1
细胞骨架是活细胞的重要结构,研究细胞骨架的形态对于进一步研究其功能具有重要意义。本研究以洋葱为材料,设置了4个不同的1％Triton X-100抽提非骨架蛋白时间（10min、15min、25min、40min）对洋葱细胞骨架显微观察的关键条件进行了优化,同时分析了细胞环境温度（-18℃、4℃、20℃、50℃）,紫外线照射活细胞（0min、60min）,0．1mol／L Ca^2＋处理及0．1％秋水仙素处理对洋葱细胞骨架形态观察效果的影响。结果表明：1％Triton X-100抽提非骨架蛋白25min观察效果较好;-18℃、50℃,紫外线辐射60min,0．1mol／L Ca^2＋和秋水仙素处理均会影响细胞骨架的观察。 相似文献
14.
研究了组合工艺(高温55℃UASB反应器一常温三相好氧生物流化床)对含盐偶氮染料活性嫩黄X-6G的去除能效。试验结果表明:在水温为55℃,运行周期120d,水力停留时间18h的条件下,此工艺对于CODCr为600～1 000mg/L,含盐量为25～35g/L,活性嫩黄X-6G的浓度为40～50mg/L的染料废水,染料及CODCr的去除率可达80%～90%。 相似文献
15.
在研究猪分子标记遗传距离同杂种优势的关系时,对模板浓度和纯度、引物浓度、dNTP浓度、Mg2+浓度、不同商标的Tag酶等影响RAPD扩增的因素进行了系统的分析,在此基础上建立了适宜于本实验室研究的最佳RAPD技术体系:25(1反应体系中,含10×buffer2.5(I,MgCl21.75mmol/L,dNTPO25mmol/L,引物0.24(mol/L,Tag酶2U,模板50～100ng,1(g/(IBSA。反应程序为:94℃预变性5min,然后94℃变性1min,36℃退火1min,72℃延伸2min40个循环,最后在72℃延伸10min。 相似文献
16.
酵母菌经过不同浓度的盐溶液、低温等不同方式的逆境处理,不同时间内取样,对海藻糖的含量进行测量,得出酵母菌海藻糖含量积累的最佳单一胁迫条件是：1．2mol／LNaCl溶液处理酵母菌30min;0．9mol／L KCl溶液处理酵母菌60min;0．6mol／LMgS04溶液处理酵母菌90min;1．2mol／LCaCl2溶液处理酵母菌90min;0．8mol／LAICl3溶液处理酵母菌6h;0．4mol／LFeCl3溶液处理酵母菌3h;0℃处理酵母菌15s． 相似文献
17.
催化光度法测定亚硝酸根 总被引：3，自引：0，他引：3
赖晓绮 《赣南师范学院学报》2004,25(3):35-36
基于在硫酸介质中,NO-2对KBrO3氧化溴甲酚绿的催化褪色作用,建立了一种测定痕量亚硝酸根的新的动力学光度法.试验结果表明,在35℃时,△A趋于稳定且最大,而反应时间在10～16min内测定△A几乎恒定,本法确定在12min时进行测定.测定亚硝酸根的线性范围及检测限为0.02～1.2mg/L和0.007mg/L.大多数常见离子对测定无干扰,而Hg2+可用NaI掩蔽,V(Ⅴ)及基体干扰可加尿素制备空白予以扣除.本法简单方便,灵敏度及选择性均较高,用于雨水及池塘水中微量亚硝酸根的测定,结果较满意. 相似文献
18.
在pH=7.40的Tris-HCl缓冲溶液中,采用荧光光谱法和粘度法研究了8-羟基喹啉（HQ）与鲱鱼精DNA的作用方式.用摩尔比法确定了HQ与DNA的结合比为12∶1.通过热力学研究得出,在27℃时HQ与DNA之间相互作用的Kφ27℃=3.844×105L/mol,热力学函数ΔrHφm=-5.08×104J/mol,ΔrGφm 300.15K=-3.2×104J/mol,ΔrSφm=-62.6 J/（mol.K）.结果显示该反应为焓驱动.实验表明HQ与DNA的作用方式为部分嵌插与静电作用方式. 相似文献
19.
目的：消除血红蛋白和胆红素两种因素对碱性苦味酸速率法测定肌酐的负干扰。方法：用苦味酸速率法测定未溶血、人为溶血、人为溶血后加0．88mol／L H2O2 37℃水浴20min、人为溶血后加0．88mol／L H2O2 37℃水浴30min、未溶血加0．88mol／L H2O2 37℃水浴20min五种处理的血液样品中肌酐值。结果：其他四组与第一组差异均有统计学意义（P〈0．01）;第三组与第二组、第五组测定结果有差别（P〈0．01或P〈0．05）,而第三组与第四组的测定结果则无差别（P〉0．05）。结论：用0．88mol／L H2O2处理溶血样品后,再进行肌酐测定。可消除血红蛋白和胆红素对肌酐测定的影响,使测定结果更真实。 相似文献